DE10297001T5 - Information reproduction system with improved error detection and reconstruction - Google Patents

Abstract

Procedure for finding errors in a data volume with the following steps:
Storing an original data volume;
Reproduce the original data volume;
Examine the reproduced data volume for errors;
Correcting an error in the original data volume based on information obtained from examining a corresponding error in the reproduced data volume.

Description

CROSS REFERENCE ON APPROPRIATE REGISTRATIONS

The present application is a continuation-in-part registration of those filed on June 28, 2001 U.S. Patent Application No. 09 / 894,422, which is incorporated herein by reference introduced be.

STATEMENT REGARDING FEDERAL FUNDING RESEARCH

Not applicable.

AREA OF INVENTION

The present invention relates to generally data storage and, in particular, data reproduction systems.

BACKGROUND THE INVENTION

Included as known in the art Computer systems, which are big Process and store amounts of data, typically one Processor or multiple processors used in conjunction with one Data storage system in which the data is stored. The Data storage system can be one storage device or multiple storage devices, for example Disk drives included. To keep data loss to a minimum, can Computer systems also a reserve storage system or backup storage system in connection with the primary Processor and the data storage system included.

Known reserve storage systems can be one Reserve storage device (e.g. a tape storage device or any other storage mechanism) together with a system for inserting the data into the storage device and for recovery of data from the storage device. Copied to keep a reserve the host used data from the proportional Data storage system via the network into the backup storage system. Thus, an actual File about the network is transferred to the backup storage device or backup storage system.

The proportionally used storage system corresponds the actual physical memory. For writing the reserve data over the network into the reserve storage system the host first converts the reserve data into file data um, d. H. the host takes the data from the physical storage system level and converts the data into the application level format (e.g. a file) about a level of a logical storage volume manager, a file system level and the user level. If the backup storage device the data file receives the reserve storage system can then record the file at the user level and in their appropriate format for the backup storage system convert. If the backup storage system is a tape storage device, then the data is converted into a serial format of blocks or segments.

The EMC data manager (EDM) is in able to maintain such reserve and reconstruction over a To carry out data network, as described in numerous publications which is from company EMC; Hopkinton, Massachusetts are available, including the EDM User Guide (Network) "Basic EDM Product Manual". An example of a known backup memory architecture, in which a direct Use connection between the proportional Storage system and the reserve storage system is manufactured in U.S. Patent 6,047,294, assigned to the assignee of present invention transferred and the title “Logical Restore from a physical backup in computer storage system ", where this patent is incorporated herein by reference.

For size Databases can Tape-based data reserve and reconstruction systems used which are well known in the art. Generally will Files, databases and the like on the tape medium at certain times copied. Typically a periodic reserve or a periodic backup of the data carried out to the loss of data due to software errors, human errors and hardware failures prevent. If an error is found in an online database can, for example the data held in reserve is reconstructed for recovery of the data. While the reconstruction focuses on obtaining the data held in reserve data reconstruction refers to the entire process, which applications have access to the recovered data can and can use them. Transactions since the time of reserve holding can be carried out again so-called repeat entries are used.

Tape backup and reconstruction systems have a number of disadvantages. Due to the considerable amount of time and effort involved in maintaining and reconstructing data on the tape, such operations are performed relatively little. The longer the time between reserve maintenance and reconstruction, the more complicated and time consuming the entire recovery process becomes, for example, because this makes it difficult to determine the point at which an error occurred. In addition, improvements in the data recovery process, for example, lead to faster tape access times, only little progress overall Data recovery process.

Next can be on data on a tape cannot be accessed until they are reinstalled on a plate are. Only when the data is saved again can a Host computer check the data. The data must for every transition be reformatted between the tape and the plate, which is considerable Processing effort and loss of time means.

Another disadvantage of using data storage systems on a tape storage basis relates to the data recovery process itself. Judged after, for example, an error an operator, for example a database administrator, the error in an effort to find a way to correct the mistake. The administrator must however with the restrictions deal, imposed by the nature of storage on a tape are. For a database that is critical to large tasks can make it unacceptable be expensive to shut down the database and restore and re-storage from the tape. If any possible the administrator will try to repair the database. The Danger of destruction the entire database, which leads to additional errors, and The possibility, not being able to cure the mistake are considerable, however.

In addition, it is not always known at what time the database became corrupt. In the case, in which data is restored and re-stored from the tape the correction of the error can be repeated and time consuming process. The administrator can select a first set of tapes for recovery, after which examining the database to determine if the error is corrected. If this is not the case, then another group of tapes must be used for the recovery used, which typically corresponds to an earlier reserve measure. The data investigation steps are then performed until the error has been corrected.

Once the error is corrected then the error can be reintroduced into the database, if later Reserve transfers Repeat entries are added to the database. The point at which the error occurs must be identified become. The time and effort with those to be repeated Tape recoveries and associated with fault identification are, can be quite substantial.

A well known attempt to identify Errors included the so-called data cleaning tools. These tools, which ones can run periodically, are used in an effort to correct errors as soon as possible discover. While Such tools or tools may discover errors are many production databases, for example those from sellers used on the internet, critical of their job and can do not handle the load required for such tools is. In many applications there are data cleaning tools and data cleaning tools not a practical one Possibility.

There are also times when it is desired is to restore only part of a database. Known Enable systems however not an easy recovery of less than the entire database. While a recovery of part of a database in systems with conventional Data retention and data recovery may be high Degree of skill required to manually part of a database restore. It is therefore desirable to discuss the previously discussed and overcome other disadvantages.

SUMMARY THE INVENTION

The present invention provides a data recovery system with configurable copying of Volume of data, the system considerably detecting errors and improves the correction compared to conventional data retention systems. While the invention is primarily based on the recovery of databases is shown and described, it is understood that the invention is applicable to other systems where it is desired Detect and eliminate errors in stored data.

According to one aspect of the invention an information recovery system copies an original data volume or several original data volumes to examine the integrity the copied data volume or the original data volume. When discovered of an error, the system can correct the error by repair and / or data recovery can be used. After a successful one Error detection can the data volumes, which still contain the error, are then corrected become.

In another aspect of the invention an information recovery system causes a facility of partial database copies, for example, a selected table space or more selected Table spaces. With this arrangement, a user can select from table spaces for recovery a copy of an original Select database. In one embodiment The partial setup can be started in a variety of ways become.

In accordance with another aspect of the invention, an information recovery system effects automatic selection of copy storage. With this arrangement, the information recovery system automatically searches for possible storage spaces that can be used to replicate an existing data volume, for example wise a database, and chooses storage to meet predetermined requirements to avoid the need for a database administrator to manually identify storage. While the invention is shown and described primarily in connection with the copying of databases on disks, e.g. Oracle databases, it is to be understood that the invention is generally applicable to storage systems where it is desirable to keep digital information in reserve different copying technologies or replication technologies for the subsequent restoration.

In one embodiment, an IR server wins a list of possible ones Copy memory locations, for example BCV's, production data volume for example Standard volume of which reproduction or copy has been requested is. A user can require certain BCV's to be mandatory Have criteria, such as a BCV storage is previously configured by the user. The system then dials possible BCV's for everyone Standard volume and assessed each pair of standard volume BCV. In one embodiment For example, an assessment of the pair based on the level of work equipment stress Disk drive spindle, bus, etc. for the standard volume BCV pair certainly. The resources can be weighted to the level of deterioration in work to reflect due to the resource's demands. A group rating is determined from the couples' ratings for assessment, whether an acceptable storage solution has been found.

It is understood that a certain Terminology used for example BCV, standard volume and other expressions be to understanding to facilitate the invention and yet this is not a limitation of Invention expressed.

SHORT DESCRIPTION THE DRAWINGS

The invention is made even more comprehensive the following detailed description in conjunction with the accompanying Understandable drawings, in which:

1 Figure 3 shows a schematic illustration of an information recovery system in accordance with the present invention;

2 Figure 3 is a diagrammatic representation of an example of a screen image for the system of 1 is;

3 a diagram of another example of a screen image for the system of 1 shows;

4 Figure 3 is a schematic block diagram of a data storage network that is part of the system of 1 can form;

5 a schematic representation shows which further details of a data storage network can be recognized;

6 Fig. 3 is a flowchart showing an example sequence of steps for recording logical versus physical storage volumes for backup or reserve and recovery in an information recovery system in accordance with the present invention;

7 FIG. 4 is a flowchart of an exemplary sequence of steps for recording and finding storage volume information in an information recovery system in accordance with the present invention;

8th FIG. 4 is a flowchart showing an example sequence of steps for creating a tree structure from storage volume information found for an information recovery system in accordance with the present invention;

9 FIG. 4 is a flowchart showing an example sequence of steps for setting up and splitting mirrors in an information recovery system according to the present invention;

10 Fig. 3 is a flowchart showing, for example, a sequence of logical information setup / establishment steps in an information recovery system according to the present invention;

11 FIG. 5 is a flow chart depicting, for example, a sequence of steps for backing up or holding data volumes in an information recovery system according to the present invention;

12 FIG. 4 is a flow chart depicting an example sequence of data volume recovery steps in an information recovery system in accordance with the present invention; FIG.

13 FIG. 14 is a flowchart showing an example sequence of steps for storage volume depletion / flushing in an information recovery system in accordance with the present invention;

14 Figure 3 is a graphical representation of the generation of storage volume checkpoints over time in an information recovery system in accordance with the present invention;

15 Figure 3 is a diagrammatic representation of the detection and correction of errors in a data volume in an information recovery system according to the present invention;

16 Figure 3 shows a diagrammatic representation of an exemplary flexible architecture for an information recovery system according to the present invention;

17 is a schematic representation of an information recovery system with partial database reproduction installation according to the vorlie shows the invention;

18 Figure 4 is another schematic representation of an information recovery system with partial database replication set up on a target set up host in accordance with the present invention; and

19 a flow chart shows an example sequence of steps to set up a partially reproduced database in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Generally, the information recovery system creates according to the present invention the possibility for users Reproductions of logical objects, such as databases and shipping systems to manufacture and reproduce the objects to restore instantly, d. H. as fast as the underlying one Storage technology allows it. While the invention in the first place shown in connection with an example storage technology and described as "Symmetrix" by EMC Corporation, Hopkinton, Massachusetts, is known, it is understood that the first connection a variety of storage technologies and operating systems applicable is. In a special embodiment the information recovery system targets various Databases, for example Oracle and SQL Server databases. The system enables it users, a database or part of it, for example reconfigure one or more table spaces for reproduction. The configured part of the database is used as a reproduction object (RO) designated. That means the reproduction object (RO) describes the application to be reproduced. For each RO describes an activity or describe several activities, how to reproduce the object of reproduction should. One example contains information on how to use the database traffic, for example online or offline, before enrollment or after enrollment, installation and recovery options and memory selection criteria. The activities can be as needed or for predetermined Times run according to schedule. Installation details, for example where and how, during the Creation of the activity To be defined.

The activity can be saved by the System can be selected in a variety of ways. For example the system can use free or previously set up business continuation storage volumes (BCV's) search. According to this selected Use denotes business continuation storage volume or BCV's one Standard volume mirror as part of the database. Even users can Define attributes on BCVs, to form storage pools and storage according to attributes in activity too choose. The user can also explicitly assign BCVs to standard devices (STDs).

1 shows an example of an information recovery system 100 according to the present invention. An IR server 102 which has a permanent memory 104 contains, handles activity requests from IR users of desktop devices 108 , A network server 102 forms an interface to a local area network (LAN) 106 to connect, for example, to the user desktop devices 108 to enable a user interface, such as a browser 108 and / or a command line interface (CLI) 108b , and an IR application 108c can contain. The IR server 102 can also be an IR Reproduction Policy Manager 102b within an IR daemon 102c for controlling and coordinating reproductive activity for the storage units 110a within a storage area network (SAN) 110 included, which are visible to the respective application hosts. The IR server 102 can be a reproduction policy manager or a replication machine 102b included for each replication technology set up to help make decisions regarding which memory to use for a given replication. In one embodiment, the process machine or policy machine 102b provided as a dynamic library connected to the IR daemon. Static status information about existing productions and the corresponding memory is in the IR database 104 stored, which can be provided as an SQL server database.

The system 100 also contains application hosts 112 , for example Oracle database server hosts, which use an application agent 112b under customer control 112a can stand, as well as a storage service module 112c , The application agent 112b in the IR application customer units processes user databases which are located in the storage area network 110 are located. The named customer control module 112a can be provided as a daemon and handles and issues customer operations. The application agents 112 , for example one-piece units for every feasible application, handle work requests. The IR application customers 112 may also communicate with third-party sellers, for example, about calls to use a third-party product to keep a replica of the user database in reserve or backup. It goes without saying that hosts which are used to set up reproductions also include the application hosts 112 could be.

While three separate hosts are shown herein, it should be understood that there is a Be on a single host or machine users or multiple users, an application customer or multiple application customers and an IR server or multiple IR servers. It is further understood that the exemplary embodiments, architectures and configurations shown can easily be modified by a person skilled in the art in this area in order to meet the requirements of a specific application, without thereby departing from the basic idea of the invention.

2 shows an example screen image 150 an IR controller for an information recovery system according to the present invention. The screen picture 150 can be a hierarchy of objects 152 contained in the IR system, for example users, application hosts, applications, memory, the timetable and reproduction objects (RO's). The example shows a reproduction object with the designation "Parts DB / TS1 / TS2" 154 fanned out to the activities 156 and the cases 158 to show this reproduction. The activities include the entry 160a "Create CKP on Jupiter", the entry 160b "Disaster CKP" and the entry 160c "Regularly on schedule". The cases 158 show the check points or reproductions that have been created for the reproduction object.

Generally the hosts and the applications for the system visible after setup. If the hosts and the applications are set up, they are registered in the IR daemon database.

3 shows an example screen image 200 to create new reproductive objects (RO's). To create new reproduction objects, the user activates a download menu and selects "File", "New" and "Reproduction Object" to display the new screen 200 for the reproduction objects to achieve. The user then specifies the application host in the application host field 202a and the application in the application field 202b for configuration based on information from the IR daemon database of set up application hosts. For a given host and application, each case of the application can be in the case field 202c are reproduced. The user selects a case and assigns a name to the new reproduction object in the name field 202d to.

Additional screens (not shown) the user for additional Consult information. For example, another screen image the user to provide application-specific information about the Prompt reproduction object, such as how to access the Database should be taken (user name and password), as well as which parts of the database are kept in reserve should, for example the entire database, table spaces for an Oracle database, etc. Another screen allows the user to do activities for the reproduction object to accomplish. There are many activities, which are individual or according to plan for certain Can walk times. More specifically, an activity can reproductions on a regular schedule can create a decision support database and can carry disaster recovery.

In one embodiment has a reproduction or an exam point an expiry time, d. that is, a time over which reproduction remains valid. The user can specify whether it is assumed that the checkpoint (reproduced database) is set up. This information may be needed if a reproduction technology (RT) is chosen, because not all Reproductive technologies, settable copies of the checkpoint enable. When making the storage selection, the user can use a reproduction technology choose or may allow that System chooses the reproduction technology as mentioned above.

In addition, the user can for each activity Provide attributes for describing the setup, storage and application are. Furnishing attributes define what happens to the object if it is set up, for example, restore the database, running a test program and running a Reserve recording on tape. Storage attributes determine which Memory is to be used to make the reproduction. Application attributes determine when the reproduction is made and which application-specific things are carried out have to, for example placing the database in online reserve mode and the use of a user font to shut down the database.

Choosing the setup options for the Reproduction object allows the user to specify things which performed after a reproduction has been made. the same Group of options can be presented to the user if the User manually selects to set up a reproduction. A Option that the user has is whether to reproduce is established and restored and where it is made visible becomes. Running an activity can set up the Reproduction include which is fully or partially set up becomes.

After choosing how to set up the application, the user can choose what to do with the application, for example by choosing which program to run, by letting a reserve run and setting up the application after completion. Multiple programs or reserves can be selected for implementation. Upgrading includes shutting down the application and removing any memory references that ge were created to make the replication visible in the target operating system.

The storage can be the IR system expressly be made known, either by assigning attributes for storage or by express Mapping standards to replication storage. In a special embodiment is used in the screen to define attributes of storage the user a list of BCV's offered, which in the data storage device, for example Symmetrix, added to the customer machines. The user can then BCV or several BCV's choose and assign them attributes.

4 shows further details of an information recovery system 300 with a data storage system 302 according to the present invention. In one embodiment, the data storage system 302 (which is within the storage area network 110 of 1 may be based on a Symmetrix Integrated CacheDisk Array System available from EMC Corporation Hopkinton, Massachusetts. Such a data storage system and its implementation is fully described in U.S. Patent 6,101,497, issued August 8, 2000, and also in U.S. Patent 5,206,939, issued April 27, 1993, both of which are owned by EMC, the Zisionar of the present invention, which are incorporated herein by reference.

Generally speaking, a local volume is reproduced in a work continuation volume (BCV). A local system that uses mirroring and allows access to production volumes while the backup or reserve is being performed is also described in U.S. Patent 6,101,497, which is incorporated herein by reference. The data storage system 302 contains system memory 304 and sets or multiples of multiple data storage devices or data stores 306a . 306b , In an exemplary embodiment, the system memory contains 304 a buffer or cache. The storage devices 306 can be disk storage devices or optical storage devices and the like. However, in an exemplary embodiment, the storage devices are disk storage devices. The storage device 306 represents a group of storage devices in any of a variety of known configurations.

Host adapter (HA) 308a . 308b form the connection between the host system 310a . 310b and system memory 304 , and plate adapter (DA) 312a . 312b form the paths between system memory 304 and the storage device groups 306a . 306b , A bus 314 connects the system memory 304 who have favourited Host Adapters 308 and the plate adapter 312 together. Each system memory is used by different elements within the respective systems to transfer information and to cause cooperation between the respective host adapters and disk adapters.

An optional backup storage system or reserve system 350 can with the data storage system 302 get connected. The backup storage system can be provided as an EMC data manager (EDM) connected to the data storage system, as described in the user manual “Symmetrix Connect User Guide, P / N 200-113-591, Rev. C, December 1997 " , available from EMC Corporation. The direct connection between the shared storage system and the backup storage system can act as a high speed data channel 352 be formed, for example as a SCSI cable or as a fiber channel cable or several fiber channel cables. In this system, the user can be allowed to reserve data over the network or the direct connection.

The backup system 350 includes a backup / restore server 354 , a logic 356 as part of the server and a storage tape library unit 358 , which may include a ribbon-shaped medium (not shown) and a robot seek mechanism (also not shown) as provided in the preferred EDM system.

In general, the data storage system works 302 depending on commands from the host systems 310 via the host adapter 308 , The host adapter 308 transfer commands to a command buffer, which is part of system memory 304 is. The command buffer stores data structures and describes requests that the host adapters generate. The disk adapter or disk adapter 312 respond by performing an appropriate operation using the information in an instruction buffer. The selected disk adapter then initiates a data operation. Read operations transfer data from the storage devices 306a . 306b to the system memory 304 via an appropriate plate adapter 312a 312b and a subsequent data transfer from system memory 304 to the corresponding host adapter 308a . 308b when the host system 310 initiated the data write process.

It is understood that the computer host systems 310 can be any conventional computer system, each with an operating system, for example systems available from Sun Microsystems that use the Solaris operating system (a version of Unix), an HP system that runs on HP-UX (a Hewlett-Packard -Customer running with a Hewlett-Packard version of the Unix operating system), or an IBM system running with the AIX operating system (an IBM version of Unix), or any other system with an associated operating system, for example the WINDOWS NT operating system. The store system can be any conventional storage system, including a Symmetrix storage system, as described above.

It is now a brief description of concepts given for the understanding of the present invention are helpful in this field are known in the art. A physical plate is transformed into a "physical Volume "for use formatted by management software, for example the software Logical Volume Manager (LVM), which is available from EMC. Any physical Volume is divided into individual blocks split up, which as physical Sections or as physical Sub-areas are to be designated. Physical volumes become too combined into a "volume group" Volume group is thus a collection of plates, which as a large storage area be treated. A "logical volume" consists of one certain number of physical Sections or sub-areas that consist of a single volume group come. A "file system" refers to a structure or collection of files.

Another useful terminology is briefly described below, which can be more fully understood by referring to the 497 patent incorporated herein. When a mirror is set up, the data storage system creates 119 a mirror image (a copy or reproduction) of a source volume or standard volume. If the preferred Symmetrix storage system is used, such a mirror is referred to as a work continuation volume (BCV), generally also referred to as a mirrored disk, and in this context is to be referred to as a BCV device. If data changes in the standard volume, the same changes are made immediately on the mirrored disk.

If a mirror is "split off", then isolated the Symmetrix duuuate storage system is the mirrored version of the Disk and no further changes are made to the mirrored volume. After completion a spin-off can be the primary Plate continues changes experienced, but the mirror keeps the dates of the time that existed at the time of the spin-off. Mirrors can are "synchronized" in any direction (i.e. from the BCV to the standard or vice versa). For example, changes at the standard volume that occurred after a split to the mirror, on the BCV volume or the mirrored plate be made. This aligns the mirrored plate with the standard volume. When synchronizing in the other direction can be the primary Plate to be made to match the mirror. This is often the last step while a restoration.

Operation of a BCV device and its corresponding BCV volume or its corresponding BCV volumes becomes easier with records understandable, which are stored in logical volume and this proves helpful for the understanding of the present invention. Any given logical volume can be in part or all of a physical disk drive or two or more disk drives can be saved.

It is on 5 Referred. In this particular embodiment, operations on a series of physical disks are controlled in logical volume sizes. The segmentation or translation of physical disks into logical volumes is well known in the art. A disk adapter (not shown) forms the interface between the logical volumes 360 to the bus of the data storage system. Each of these volumes 360 is defined as a business continuation volume and is assigned to a BCV device. Each BCV device includes a standard disk controller and associated disk storage devices that are configured to independently support applications and processes. The use of these BCV devices enables a host, for example the host 310a , which is referred to as the "source" host system from now on, instantly copies the data into the standard volumes 362 to use. In conventional operation, at least one BCV volume is typically assigned to each of the host devices that process a data record at the same time. However, as explained below, the BCV volumes that are set up for use by one host can be accessed by another host, such as the host 310b may be used, which will be referred to as the "target" host system from now on.

The source host 310a may continue online transaction processing (e.g., database transaction processing) or other processing without affecting or affecting the standard volumes 362 has while their respective mirror images in the BCV's 360 to be used, a data reserve or a data backup in cooperation with the backup system 302 to set up. However, the BCV's can be set up for use on another host essentially automatically under the control of a computer program, without the need for operator intervention all the way.

The direction of the data flow for the reserve device or the backup goes from the data storage system 302 to the backup system 350 as by the arrow 364 is indicated. The direction of data flow for recovery goes in the opposite direction to the data storage system, but the BCV's can 360 to be set up on another host, which is from demje the original device according to the method of the present invention is different.

The optional backup system 350 , such as the EDM system, offers various options for controlling mirroring behavior before and after a backup or restore. Mirroring methods are well known to those skilled in the art. Examples of pre-backup mirroring options include shutting down the mirrors, determining that the mirrors are shut down, shutting down the mirrors when needed, and shutting down the mirrors after installation; and the options of the mirrors after backup include activating or powering up the mirrors, leaving the mirrors in the deactivated state, and leaving the mirrors as they are found.

The system creates a copy or multiple mirrored copies of data (BCV's), which are copies of a volume or multiple volumes of data (standard volume). The BCV's are more traditional Set up like this in the 497 patent cited here is described. The BCV's are determined by the respective volume or the respective volume of Data in a conventional manner separated or split off, as is also the case in the attracted 497 patent is indicated.

The system looks for the logical information related to the standard volumes, which part of the volume group on the source computer system 310a are. A record of the logical information on physical devices in the source computer system is created. In one embodiment, the recording can be provided as an XML message. Alternatively, the record takes the form of a unit file, which can be converted into a tree structure to enable the logical information to be checked quickly. This record is used to build up an essentially identical logical configuration on the target computer system 310B ; preferably after checking the logical information by using a tree structure configuration of the logical information.

The logical configuration is used to create a duplicate of the BCVs on the target computer system (referred to as installed target BCVs). The newly created target BCVs then become part of a second volume group on the target computer system 310b ,

The backup system performs a number of functions before the data transfer. A find / record function causes a search and recording of logical objects to physical devices on the source host 310a and contains information such as physical volume and logical volume, volume groups and file system information. A setup / split-off function builds BCV's or splits them from standard volumes, depending on the pre- and post-mirroring procedures that are on the source host 310a are effective.

A build / install function exports the BCV's, which are on the source host 310a are set up to the target host 310b , It creates volume groups, logical volumes, and file system objects on the target host system.

An optional backup / restore function introduces Backup the target host BCV data which has been exported or transferred from the source host are. The dismantle / delete function removes all Volume groups, logical volumes, and file system items the target host.

6 shows an overview of the overall reproduction setup process. In step 400 the system records logical objects in physical devices on the source host. In step 402 the logic sets up and then splits off standard volumes in BCV's according to the mirroring process that is effective on the source host (which can be accomplished by calling another function on data storage systems). In step 404 the system builds and installs on the target host so that the BCV's are exported or transferred to the target host. The step 408 is a cleanup step in which all volume groups, logical volumes and file system objects are removed from the target server.

7 is an overview of the steps in the recording and search process. In the step 500 the search / record process begins at the source host. At the source host is in step 502 the file system searched and in step 504 the logical volume is searched. The volume group information is sent to the source host in step 506 searched. In step 508 For example, the record can be created as a unit file or other relatively effective data structure for the gathering and use of the information.

It is now on 8th Referred. In one embodiment, the step 600 the logical volume information found, which can correspond to a unit file, is used to generate a tree structure. This structure can be built through a UNIX function call of information in the record files, as described above. It can be built on both the target host computer system and the source host computer system. The structure is called a tree because the volume group information is used as the root of the tree and the branches represent the device information within the group and the logical volumes within the group. The tree structure serves in the step 602 to check the accuracy of the on drawing file before it is sent to the target host. The tree is in a record preferably as a unit file in the step 604 reshaped. This unit file record is then in the step 606 sent back to the target host.

Alternatively, the search can be carried out in a way similar of those as carried out by the EMC Data Manager (EDM), that is well known to those skilled in the art. In one embodiment the recording is sent as an XML message.

It is on 9 Referred. The process of setting up and splitting off a backup system starts with the step 700 , A mirroring policy, if one is in place, becomes the step 702 checked. In step 704 a request is made to determine whether BCV's have been set up in accordance with the mirroring policy. If the answer is "no", then in the step 706 BCV's set up. The BCV's are from the source host in the step 708 cleaved. The BCV's are in the step 710 not made available to the host.

Now be 10 considered. The process of starting building / installing logical information such that the BCV's can be installed on the target host continues in the step 800 on. The volume groups are in step 802 generated on the target host. Logical volumes are on the target host in step 804 checked. The file system is checked and started on the target host, which in step 806 happens. The item installation can now in the step 808 be completed with the logical information relating to the BCV's on the target host.

As in 11 is shown, the newly installed target BCV's can now optionally be kept on tape in reserve, which in step 900 is shown. The application is then in the step 902 turned off on the target host. Following the backup of the target BCV's found in the step 904 Cleaning up and notification steps take place.

When the software application is on the target host and the source host is a database, then the information related to the data, including a backup undergo, with the effect that essentially the entire Database kept in reserve or backed up becomes. Important information from the database includes any Transaction data represented by the database operations, as well as related Control files, table spaces and archives / repeat entries.

Regarding the databases now further terminology discussed. While the terminology for an Oracle database one skilled in the art will recognize that other databases are used can, without deviated from the idea of the invention.

Control files contain information about the Oracle database including Information that describes the location where the data files are located and registration files. Data files can be files in the file system of the operating system. A table space is the lowest logical Layer of an Oracle data storage structure. The table space contains one Data file or multiple data files. The table space provides the finest subdivision for the arrangement of data about Data files.

There are archive files in the database, which as repeat entry files or simply as repeat entries are known. Here it is where everyone Information to be restored. be kept. Without the retry entry file would cause the data to fail make it unrecoverable. If a registration circuit occurs, then the entry records are filled in the repeat entry file copied to an archive entry file when archiving possible is.

It is now 12 considered. Here, as shown, the process for restoring standard source volume in step begins 1000 for the optional backup system. In step 1002 the system makes a request to determine whether the recovery should be from the BCV's on the target grate or from anywhere else. According to the answer, the standard volumes of the BCV's or the tape set up on the target host, for example in the steps 1004 respectively. 1006 synchronized. With the step 1008 begin the notification and cleanup steps, which are generally in 11 are specified.

As in 13 shown starts in the crotch 1100 the cleanup / dismantling process. The. BCV's are in step 1102 removed from the target host. This can be achieved with a UNIX dismantling command, for example. The items that relate to a volume group, logical volumes, and file systems are taken from the target host in the steps 1104 and 1106 away. The cleanup or deletion is in step 1108 completed. The BCV's are rebuilt in the source host (ie, made ready for the host), which in step 1110 happens.

14 Figure 10 shows an example of a checklist or reproduction schedule for an information recovery system in accordance with the present invention. At around 8:00 a standard volume STD, which can contain an Oracle database, for example, is reproduced on a corresponding BCV, CHKP A, as described in detail above. At 12:00 the next scheduled inspection time occurs, at which the standard volume is reproduced on another BCV, namely CHKP B. At around 1:00 am, an error is discovered, for example by a data cleaning tool that at about 2:00, after a certain assessment period, the standard volume is reproduced on a demand BCV, CHKP OD. The 4:00 exam time for the next BCV, CHKP C can occur on schedule, provided the error is corrected and the standard volume STD is current. Additional requirements check points can be provided as described above, if desired.

15 FIG. 10 shows an example process of recovering from a data error, such as a transaction error in a database, in accordance with the present invention. A data error occurs at a time T _e , after which the system continues to run for a time TLE while the error is hidden, ie unknown to the system operator, for example the database administrator. As is well known to those skilled in the art, the errors can have a variety of causes, including software errors, hardware errors and / or failures, and human error.

In one embodiment there is a data volume reproduction, for example a copy of the database, on a disk as BCV, which is installed on a remote host and with so-called Data cleaning tools is checked. Data cleaning tools to investigate data integrity are well-known to the expert known. While for example understandable is that a Variety of data cleaning tools can be used to Assessing the integrity of the reproductions can be a suitable one Data cleaning tool from the Patrol product family from BMC Software of Redwood Shores, California. Since the data according to the present Invention are now stored on disk, data cleaning can significantly reduce the time the error is hidden, d. that is, the time during what mistakes go undetected.

In contrast, many conventional systems the failure is not discovered until a person for example a customer, the database operator for example with regard to a irregularity in the customer account. As known to those skilled in the art, can Data stored on tape is not without data recovery and recovery are checked.

After confirming that an error has occurred, passes a time TEE in which the error is assessed, for possible corrective actions set. For example, an operator or a Operator assessing the type of error can assess how the error occurred, how common the error is, what the effect of the Error is when the error occurred and how the error occurred can be corrected. The degree of operator experience, for example of the database administrator largely determines the time the for the assessment of the error is needed becomes.

While The system can make a requirement copy of the database for the error assessment to set up on another host. This enables the execution multiple assessments in parallel by an assessment team or multiple assessment teams. additionally can destructive investigations are carried out on other hosts, because the production database for further reproductions available stands.

After assessing the error, a decision is made Operator generally to correct the error during a TCE. The operator can set up backup data (from the test point) or can try to repair the production database. Through generation The operator can perform another reproduction before attempting repair make a free attempt to repair the living database. This means that the operator can attempt to repair with a risky "shot in the dark" because multiple checkpoint backup data exist. In the case where the operator's attempt to solve can't get the bug fixed or the bug still can make worse the backup data from an exam point easily re-established, made and made from the repeat entries be updated. Another copy of the database can be used to try additional possible solutions to do. Alternatively, you can solutions tried a copy of the database before modifying the production database become.

If a re-establishment versus a Repair is given the default, then the user must decide which backup data should be saved again. Ideally this is the youngest Backup before the database becomes defective. If the exact Time when the error occurred is unknown then the Estimate users which backup data should be set up again.

In known systems the Users can reset the selected backup data. After completion the re-establishment, which can take place many hours later the user check whether the selected Backup data are free from errors. This is not the case, then the Users to further restore additional backup data make. Such multiple restores or rebuilds are made unnecessary by the IR system according to the present invention, because the user selected backup data can install on another host and this backup data after Can investigate errors. As soon as error-free backup data is found, a single re-establishment can take place.

In many known systems, the so-called surgical repair of the production database is the preferred option due to the time and effort involved in re-installing direction of the data from the tape is connected. For relatively large databases, such as more than one terabyte, data recovery from tape can take many hours. In addition, for certain databases with critical tasks, surgical repair is practically the only option given the tremendous costs associated with shutting down a database. However, the associated risks of damage to such a database when attempting to repair an error are readily apparent.

After a time TRF after re-establishment of the checkpoint the forward roll process tries the database with transactions that have occurred since the copy of the database was frozen, and which in the repeat entry RL are recorded. The forward roll process repeats as the database should be checked for errors while the recorded Transactions are entered into the database. By incremental Before rolling up or scroll forward the database will be updated at certain points. If a mistake is discovered, the Forward roll process only too run back to the last correct point. Conventional systems on a storage tape basis due to the incompatible formats this possibility between tape and plate.

It is understood that an operator easily the special error detection and correction steps depending on the requirements of a particular application can vary. For example can checkpoints after changeable Timetable and as needed for use when finding an error correction solution become.

16 For example, shows an architecture of an information recovery system that flexibly and easily works with a variety of application agents, operating systems and reproduction technologies. In general, an IR core communicates with a graphical user interface (GUI) or a command line interface (CLI) via an application programming interface (API) to enable information reconstruction. Different application agents A, B and C communicate with the IR core via a corporate application API. The IR core can work with a variety of customer operating systems and reproduction technologies. A separation of applications and reproduction technologies with a common interface to the core enables the supply of new applications and reproduction technologies without changing the core. For example, new reproduction technologies, which include new hardware, new host-based production software and / or third party copies, such as SCSIXCOPY devices, can be easily added. New databases and applications can also be easily added, including new file systems, new relationship database management systems (RDBMS), and new financial and e-mail applications. New user interfaces, new font formulas and new host platforms can also be easily maintained.

In another aspect of the invention part of a database reproduction can be built into a host computer become. While the invention only in connection with table spaces in an Oracle database it is understood that the invention extends to others Database types and database components is applicable. Also understands it is that the Oracle expressions used to understanding to facilitate the invention, however, no limitation of the Derive invention of a particular database type or configuration is.

The 17 and 18 which have a certain similarity to it 1 have an example of an IR system 1200 with the installation of a reproduction of a database part according to the present invention. The IR server 1202 contains an IR daemon 1204 for handling reproduction requests from host computers, for example IR users 1206 , IR application customers 1208 work as a database server DBS ( 18 ) for applications, for example Oracle databases, which are stored in volume groups VGS in the storage area network SAN. An IR user 1206 or a facility host MH ( 18 ) has a view of a reproduced database RDB, which has been reproduced from an original database ODB.

In the embodiment shown, the production database or original database ODB is located in a storage area network SAN and runs on the database server host DBS. The original database ODB contains a first, a second and a third table space TS1, TS2, TS3 together with the system information SYS. The reproduction database RDB of the original database ODB also contains corresponding table spaces TS1R, TS2R, TS3R and the system information SYSR. The creation of the database replica has been described in detail above. The reproduction database ODB is for an IR user, for example the facility host MH ( 18 ) visible. It goes without saying that the facility host MH and the database server DBS are essentially the same, for example running with the same operating system, etc

The IR daemon runs as described above 1204 on the IR server 1202 , The reproduction information, for example recording files, is in the IR database 1210 contain. The IR database has the information required to install and start a reproduction. This information is obtained during the creation of the reproduction, as also described above.

The customer control module or daemon 1212 ( 17 ) runs on the database server DBS and the facility host MH. The customer control module running on the facility host receives the data volume record file along with other necessary information from the IR server 1202 to set up the reproduction database RDB.

In general, the system can partially reproduced database, for example table spaces, which were selected by a user in the manner described above, run in a variety of ways. For example the operator the first table room TS1 for the start choose, so that the second and third table spaces TS2, TS3 are not taken into account. After setup, the first table space TS1 is ready for use available through an operator.

In one embodiment, a partially reproduced Database, for example the first table space TS1, in a restored one Mode, in a restored mode for reading only and in one mode can be designed without recovery, as described below becomes. More fashions to fulfill The requirements of a specific application are without for the specialist further apparently.

19 shows an example sequence of steps to start a reproduction of a part of a database according to the present invention. In step 1300, the facility host of the record database of the reproduction database wins from the IR database via the IR server. A database server to control the reproduced database is then in the step 1302 created in the facility host. Creating the database server can include importing volume groups, starting volumes, and setting up file systems, for example. In the step 1303 the system copies the corresponding backup control file as well as archive entries, the init <sid> file and the password file to the required location in the facility host. In the step 1304 the relevant database, for example the reproduced Oracle database, is installed in the target device host, as described in detail above. It is understood that the replica can be built into a target host in which the reproduced database does not already exist. This means that the system expects that the installation host has installed the Oracle application and that the object to be installed is not already running on the host.

In one embodiment, the Application layer of the customer tax daemon a record or a tree file that describes what needs to be restored. The original Tree will during the reproduction of the application is generated and is in the IRD catalog / database stored on the IR server. This record is for customer control available made that runs on the facility host. The tree contains what is to be set up and is built up from the user requirements. So choose the user gets a partial tree from the original tree. This partial Tree is compared to the original tree, which describes what is contained in the reproduction database. This makes it possible to set those table spaces for the customer control daemon, for example TS2 and TS3, which do not need to be restored. The Registration files can copied over to the target host as well as other information files for example for Oracle applications the initinstance.ora file and two backup control files (one Version for Read alone and a regular one Version).

To start in recovery mode, be in step 1306 renamed the database volume groups and / or raw objects from the original host names to new names in the target facility host. For example, Oracle determinations are carried out to make the name changes current to the Oracle database. It is understood that the password file is transmitted from the IR database for reproduction. In one embodiment, the backup control files are automatically copied from the location where the real control files are suspected so that they are ready for use by Oracle. The backup control files are copied to the archive entry table of contents on the facility host. The control files are copied to the locations described by the init <SID> .ora file of the application host for Oracle applications at the time of reproduction. The description of this place is actually cataloged at the time of reproduction, for example by querying the database. Depending on whether it is a read-only restore or a normal restore, the appropriate backup control file is copied to the location described above. After copying the control files, the IR application agent software issues the relevant approvals and ownership.

After applying the recovered password file, step 1308 the unwanted information, for example TS2, TS3, is deleted, so that only the table spaces which have previously been selected for the restoration by the user, for example TS1, are restored. The restoration of the first table space TS1 is then in the step 1310 carried out. After copying the corresponding control files, the database is set up and renamed if necessary. Unwanted data files are then dropped (dropping data files updates the control files), and then the entire database is restored. Oracle ignores the dropped data files and restores only the table spaces that have been selected for installation as defined by the control files. In the step 1312 the Oracle database level is then opened and is available for use.

In the mode without recovery the Oracle layer does not issue Oracle restore commands. she holds only the tools for available to the user. That means the initinstance.ora file, the registry files, the data files and the backup control files are available. The User can then create a password file generate and restore manually.

In the start mode with reading alone the system behaves similarly like in recovery mode, but with the exception that the backup control file, which is copied to the real control file location, the fixed value version and the item is restored in standby mode and open becomes.

The person skilled in the art recognizes further features and Advantages of the invention based on the embodiments described above. Accordingly, the invention is not limited to that what has been shown and described in detail, except how through the attached claims Are defined. All Publications and comparative literature, which was mentioned here, is expressly in the totality is introduced by reference.

Summary

Information reproduction system with improved error detection and reconstruction

An information recovery system ( 100 ) contains configurable data volume reproductions ( 110 ), which can be examined for improved error detection and correction. An information recovery system also provides for the establishment of partial database replicas, for example one or more selected table spaces. With this arrangement, a user can select table spaces for recovery from a replica of an original database.
( 1 )

Claims (16)

Method for finding errors in a data volume with the following steps: Storing an original data volume; Reproduce of the original data volume;  Examine the reproduced data volume for mistakes;  Corrected an error in the original data volume based on information obtained from examining a corresponding Error in the reproduced data volume was obtained. The method of claim 1, which further comprises Steps includes:  to save the original data volume on a first number of disks; and  Reproduce the original data volume on a second Number of plates. The method of claim 1, further incorporating and the examination of the reproduced data volume with one Data cleaning tool includes. A method according to claim 3, characterized in that it further an assessment of the discovered in the reproduced data volume Error enables to determine an error correction strategy. A method according to claim 4, characterized in that it further an attempt to reproduce the volume of data reproduced, allows. A method according to claim 5, characterized in that it further the achievement of a successful repair of the reproduced Data volume in the original record on the first number of Plates. A method according to claim 4, characterized in that it the re-storage of the reproduced data volume includes. A method according to claim 7, characterized in that it updating the restored data volume with data from a repeat entry. A method according to claim 8, characterized in that it the incremental examination of the recovered data volume includes after mistakes, when the re-stored and restored data volume is updated from the repeat entry. The method of claim 9, further comprising updating of the partially recovered data volume at a point where no errors are discovered. Information recovery system, which is the following includes: a storage area network;  one with the storage area network coupled server to receive a request from a first one Host for the reproduction of a data volume group which is created by a second host can be set up and checked for errors. The system of claim 11, further comprising an information recovery application for Generation of reproduction requests contains. The system of claim 12, wherein the information recovery application is located on a host computer that communicates with the server Network is coupled. The system of claim 11, wherein the data volume group is controlled by an application agent. The system of claim 14, wherein the application agent corresponds to an Oracle database. The system of claim 11, further comprising an information recovery database contains which is coupled to the server.