JP2000305718A - Back-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a back-up device for realizing the on-line back-up of storage data, and for preventing the deterioration of system performance even during back-up. SOLUTION: This back-up device for backing-up the data of a storage part 3 connected with a host computer 1 by an input and output interface is provided with a controller part 4 connected through an input and output interface 2 which is the same as or different from the input and output interface with the host computer 1 and a secondary storage part 5 connected with the controller part 4. The controller part 4 monitors an operation flowing on the input and output interface 2, and when this is a writing instruction in the storage part 3, the controller part 4 controls the writing operation to be recorded in the secondary storage part 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backup system for backing up data stored in a storage device generally composed of a magnetic disk device or the like to an external medium such as a magnetic tape in a computer system.

[0002]

2. Description of the Related Art Generally, a storage device of a computer system is constituted by a magnetic disk device. But,
If any failure occurs in the storage device, the stored data is likely to be damaged. Therefore, it is common practice to back up important storage data to an external medium such as a magnetic tape device. ing. Since the storage data is constantly updated during the operation of the computer system, the backup needs to be performed periodically.

In the case of backing up storage data, the simplest method is to temporarily suspend the service provided by the computer system so that the data is not updated, and then perform the data backup (offline backup). This method can be performed if any backup device (such as a magnetic tape device, a magneto-optical disk device, or an optical disk device) is connected to the target computer system. When the data capacity to be backed up exceeds the capacity of one backup medium, a device with a medium autochanger device can be used.

If it is not desired to stop the service of the computer system, a snapshot of the storage data is created at a certain point in time (after recording the file structure, the storage is overwritten in response to a subsequent write request). Use the free space instead of doing it), and back up the snapshot image in the background (online backup)
There is also. In this case, dedicated backup software is required.

[0005]

There is a method as described above for backing up storage data of a computer system. In the first method (offline backup), system services are stopped during backup execution. There is a disadvantage that it must be done. Therefore, the scheduling of the backup must be determined after grasping the usage status of the system, and human-based work is indispensable. In addition, it cannot be applied to a system in which service suspension is not permitted in operation.

In the second method (online backup), the disadvantages of the first method can be avoided, but since the capacity of the storage device or the capacity of the computer itself is used for performing the backup, the backup method is generally used. The disadvantage is that the performance of the system inside is significantly reduced. This may also be a serious problem depending on the usage status of the target system, and therefore, it is often necessary to perform scheduling by a human system when performing backup.

[0007] It is an object of the present invention to provide a backup device which allows online backup of storage data and does not degrade system performance even during backup.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and achieve the object, a backup device of the present invention is configured as follows.

(1) A backup device of the present invention is a backup device for backing up data in a storage unit connected to a host computer through an input / output interface, and via the same or different input / output interface as the input / output interface. A controller unit connected to the host computer, and a secondary storage unit connected to the controller unit, wherein the controller unit monitors operations flowing on the input / output interface, and monitors the operation on the input / output interface. When the instruction is a write instruction to the secondary storage unit, control is performed to record the write operation in the secondary storage unit.

(2) A backup device according to the present invention is the device described in (1) above, wherein the controller unit has a buffer storage unit that can be accessed at a higher speed than the secondary storage unit.

(3) The backup device according to the present invention is the device described in (2) above, further comprising a plurality of the buffer storage units, and fetching the plurality of buffer storage units individually into the storage unit. When recording an operation in the secondary storage unit, control is performed so as to refer to a different buffer storage unit.

(4) The backup device of the present invention is the device according to any one of the above (1) to (3), and the secondary storage unit is a device using a replaceable medium, The secondary storage unit and the medium are stored in an autochanger, and the autochanger is controlled so as to exchange the medium. In the autochanger, a second secondary storage unit that can use the same medium as the secondary storage unit is used. A second recording unit, and a third secondary storage unit that stores an initial image of the storage unit in an initial state, wherein the second secondary storage unit and the third secondary storage unit are The medium that is connected to a second controller that can operate independently of the controller and that has been recorded in the secondary storage unit is connected to the second secondary storage via the autochanger. The second controller unit updates the contents of the third secondary storage unit to the latest storage unit by referring to a write operation to the storage unit via the second secondary storage unit. Update to match the content of the section.

As a result of taking the above-described measures, the following effects are obtained.

(1) According to the backup device of the present invention, it is possible to perform a significant backup of storage data without deteriorating system performance even when the computer system is operating online. Also,
By backing up the initial data of the storage unit, it is possible to restore the storage data at an arbitrary point in time by a write operation recorded in the secondary storage unit.

(2) According to the backup device of the present invention, when there is a difference between the writing performance of the storage unit and the performance of recording the operation in the secondary storage unit, this can be buffered.

(3) According to the backup device of the present invention, the buffering property of the speed difference between the writing performance of the storage unit and the performance of recording the operation in the secondary storage unit is improved.

(4) According to the backup device of the present invention, it is possible to quickly restore data when a storage failure occurs. Further, if the medium on which the initial image of the storage unit is recorded and the medium on which the initial image is recorded are stored, it is possible to restore the storage data at any time after the system operation starts. Further, the recorded medium can be stored without overwriting data.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a diagram showing a configuration of a backup device according to a first embodiment of the present invention. Hereinafter, the basic principle of the backup device will be described with reference to FIG.

In FIG. 1, the host computer 1
It is connected to the CSI bus 2, and a disk device or the like is connected to the SCSI bus 2. The magnetic disk device 3 is a data backup target disk, and is connected to the host computer 1 via the SCSI bus 2. Similarly, the magnetic tape controller 4 is connected to the host computer 1 via the SCSI bus 2. A magnetic tape medium 5 is connected to the magnetic tape controller 4. Data is written to and read from the magnetic tape medium 5 via the controller 4.

FIGS. 2A to 2D are diagrams showing the operation procedure of the backup device configured as described above. Hereinafter, the operation of the backup device will be described with reference to FIGS.

First, in “1. Saving initial disk image” in FIG. 2A, the initial image of the magnetic disk device 3 to be backed up is copied to the magnetic tape medium 5 via the magnetic tape controller 4. Save as an initial disk image.

Next, in “2. Recording of disk write operation” in FIG.
3 shows that the service has been started. In this state, data is read from the host computer 1 to the magnetic disk device 3 via the SCSI bus 2.
Writing is performed. At that time, the controller 4
The operation on the CSI bus 2 is snooped, and only the write operation is performed on the new magnetic tape medium 5.
To record.

Next, a data recovery method in the event that any failure occurs in the magnetic disk device 3 will be described. In “3. Recovery of initial disk image (at the time of disk failure)” in FIG. 2C, first, the failed disk device is replaced with a new disk device. At this point, since the new disk device is empty, the stored initial disk image is recovered from the magnetic tape medium 5 to the new disk device.

Next, in “4. Recovery of file update” in FIG. 2D, a write operation to the magnetic disk device 3 from the magnetic tape medium 5 on which the disk write operation is recorded is re-executed. The data in the magnetic disk device 3 is completely restored.

(Modification of First Embodiment) FIG. 2 shows an example in which the magnetic tape controller 4 snoops the SCSI bus 2. However, the same operation as in the case of a disk device to be backed up is actually performed. If it can be obtained, it is not necessary to use the same SCSI bus. For example, even if the SCSI controller on the host computer side supports two SCSI buses and one is connected to a disk device and the other to a backup device, the controller on the host computer side sends the same operation to both. This is feasible.

(Second Embodiment) FIG. 3A is a diagram showing a configuration of a backup device according to a second embodiment of the present invention. FIG. 3A is a configuration obtained by developing the configuration of FIG. 1, and the same parts as those of FIG. 1 are denoted by the same reference numerals.

In FIG. 3A, the host computer 1 is connected to the SCSI bus 2 and
Is connected to a disk device or the like. The magnetic disk device 3 is a data backup target disk,
It is connected to the host computer 1 via the I bus 2. Similarly, a magnetic tape controller (backup device controller) 4 is connected to the host computer 1 via the SCSI bus 2. Data is written to and read from the second magnetic disk device 6 via the controller 4. Data is written to and read from the magnetic tape medium 5 via the controller 4.

Generally, a backup device such as a magnetic tape device has a slower access speed than a magnetic disk device. For this reason, in the configuration example of FIG. 1, when the frequency of writing to the magnetic disk device increases, the writing to the backup device may not follow. The configuration example of FIG. 3A aims to solve this problem, and is characterized in that a magnetic disk device is connected to a backup device controller and this is used as a write buffer.

FIGS. 3B and 3C are diagrams showing the operation procedure of the backup device configured as described above. Hereinafter, the operation of the backup device will be described with reference to FIGS.

First, in "1. Recording of disk write operation-1" in FIG. 3B, the magnetic tape controller 4 snoops the operation on the SCSI bus 2 and performs only the write operation on the second magnetic disk device. Record in 6. Thereafter, in “2. Recording of disk write operation-2” in FIG. 3C, the second magnetic disk device 6 is used by utilizing the period when the load of the write operation on the SCSI bus 2 is low.
Is stored in the magnetic tape medium 5 by the magnetic tape controller 4.

(Third Embodiment) FIG. 4A is a diagram showing a configuration of a backup device according to a third embodiment of the present invention. FIG. 4A is a configuration obtained by developing the configuration of FIG. 1, and the same parts as those of FIG. 1 are denoted by the same reference numerals. .

In FIG. 4A, the host computer 1 is connected to the SCSI bus 2 and
Is connected to a disk device or the like. The magnetic disk device 3 is a data backup target disk,
It is connected to the host computer 1 via the I bus 2. Similarly, a magnetic tape controller (backup device controller) 4 is connected to the host computer 1 via the SCSI bus 2. Data is written to and read from the second magnetic disk device 6 and the third magnetic disk device 7 via the controller 4. Data is written to and read from the magnetic tape medium 5 via the controller 4.

Generally, a backup device such as a magnetic tape device has a slower access speed than a magnetic disk device. For this reason, in the configuration example of FIG. 1, when the frequency of writing to the magnetic disk device increases, the writing to the backup device may not follow. The configuration example of FIG. 4A aims to solve this problem, and is characterized in that a magnetic disk device is connected to a backup device controller and used as a write buffer.

FIGS. 4B and 4C are diagrams showing the operation procedure of the backup apparatus configured as described above. Hereinafter, the operation of the backup device will be described with reference to FIGS. In the configuration shown in FIG. 4A, the second magnetic disk 6 and the third magnetic disk 7 connected to the controller 4 are used as double buffers.

First, in "1. Recording of disk write operation-1" in FIG. 4B, the magnetic tape controller 4 snoops the operation on the SCSI bus 2 and performs only the write operation on the second magnetic disk device. 6 (first write buffer).

When a certain amount of write operation is recorded in the second magnetic disk device 6 (first write buffer), the state shifts to the state of “2. Recording of disk write operation-2” in FIG. I do. In this state, only the write operation is recorded on the third magnetic disk device 7 (second write buffer) while the write operation recorded on the second magnetic disk device 6 (first write buffer) is recorded on the magnetic tape medium 5. To be stored.

In the configuration example of FIG. 4A, recording in the write buffer and reading from the write buffer can operate in parallel, so that the buffering effect is greater than in the configuration example of FIG.

(Modification of Second and Third Embodiments) In FIGS. 3 and 4, the second and third magnetic disk devices 6,
Numeral 7 may simply be buffer storage using NVRAM, or a single drive if a magnetic disk drive is used.
It may be an AID device or a semiconductor disk device.

FIG. 3 shows an example in which the magnetic tape controller 4 snoops the SCSI bus 2.
Actually, if the same operation as that for the disk device to be backed up can be obtained, the same SCSI
The point that the bus need not be used is the same as in the case of FIG.

(Fourth Embodiment) FIG. 5 is a diagram showing a configuration of a backup system according to a fourth embodiment of the present invention. In the fourth embodiment, an embodiment including system operation will be described based on the basic principle of the above-described backup device.

In FIG. 5, the host computer 1
It is connected to the CSI bus 2, and a disk device or the like is connected to the SCSI bus 2. The magnetic disk device 3 is a data backup target disk, and is connected to the host computer 1 via the SCSI bus 2. Similarly, a magnetic tape controller (backup device controller) 4 is connected to the host computer 1 via the SCSI bus 2. Data is written to and read from the second magnetic disk device 6 via the controller 4.

The autochanger device 10 houses a plurality of drives and a mechanical transfer device for magnetic tape media, and records any one of a certain period of time, a certain amount of data, and a certain number of operations. Alternatively, the medium is exchanged at a timing according to a combination thereof. The magnetic tape drive device 11 is housed in the autochanger device 10 and is under the control of the controller 4. The second magnetic tape controller (backup device controller) 21 can operate independently of the host computer 1.

The second magnetic tape drive device 12 and the third magnetic tape drive device 13 are housed in the autochanger device 10, and are stored in the second magnetic tape controller 2.
1 is under control. Note that the second magnetic tape drive 12 can use a magnetic tape medium of the same standard as the magnetic tape drive 11. The magnetic tape medium 22 is ejected from the autochanger device 10, and the magnetic tape medium 23 is
This is a record of the initial image.

The configuration example shown in FIG. 5 basically operates based on the basic principle shown in FIG. A disk write operation from the host computer 1 to the magnetic disk device 3 is recorded on a medium set in the drive device 11. After recording a certain amount of operations,
Alternatively, after a certain period of time, the recorded medium is transported by the autochanger device 10 and set in the drive device 12.

A new medium stocked inside the autochanger device 10 is set in the drive device 11, and recording of the disk write operation is continued. In the initial state, a medium in which an initial image of the magnetic disk device 3 is recorded is set in the drive device 13, and the second magnetic tape controller 21 performs operations based on operations recorded on the medium set in the drive device 12. Then, the disk image recorded on the medium set in the drive device 13 is updated to the latest state.

Thereafter, the medium on which the operation has been recorded is ejected from the autochanger 10.

In the configuration example shown in FIG. 5, since the latest disk image is generated, there is a feature that restoration at the time of failure of the disk device can be performed quickly and easily. In addition, the media that records the ejected operations
If the initial disk image is stored together with the recorded medium (copy), the disk image at an arbitrary point in time after the operation of the system is started can be restored.
Therefore, the data can be restored not only when the disk device fails but also when the data is destroyed due to a software failure or an operation error.

(Fifth Embodiment) FIG. 6 is a diagram showing a configuration of a backup system according to a fifth embodiment of the present invention. In the fifth embodiment, an embodiment including system operation will be described based on the basic principle of the backup device described above.

In FIG. 6, the host computer 1
It is connected to the CSI bus 2, and a disk device or the like is connected to the SCSI bus 2. The magnetic disk device 3 is a data backup target disk, and is connected to the host computer 1 via the SCSI bus 2. Similarly, a magnetic tape controller (backup device controller) 4 is connected to the host computer 1 via the SCSI bus 2. Data is written to and read from the second magnetic disk device 6 via the controller 4.

The autochanger device 10 houses a plurality of drives and a mechanical transport device for magnetic tape media. The magnetic tape drive device 11 is housed in the autochanger device 10 and is under the control of the controller 4. The second magnetic tape controller (backup device controller) 21 can operate independently of the host computer 1.

The second magnetic tape drive device 12 and the third magnetic tape drive device 13 are housed in the autochanger device 10 and are controlled by the second magnetic tape controller 2.
1 is under control. The magnetic tape medium 14 is used repeatedly in the autochanger device 10.

The configuration example shown in FIG. 6 also operates basically based on the basic principle shown in FIG. A disk write operation from the host computer 1 to the magnetic disk device 3 is recorded on a medium set in the drive device 11. After recording a certain amount of operations,
Alternatively, after a certain period of time, the recorded medium is transported by the autochanger device 10 and set in the drive device 12.

In an initial state, a medium on which an initial image of the magnetic disk device 3 is recorded is set in the drive device 13, and the second magnetic tape controller 21 is recorded on the medium set in the drive device 12. Based on the operation, the disk image recorded on the medium set in the drive device 13 is updated to the latest state.

Thereafter, the medium on which the operation is recorded is conveyed to the drive device 11 and used repeatedly. In order to continuously record the disk write operation, at least two media used between the drive device 11 and the drive device 12 need to be prepared.

In the configuration example of FIG. 6, a finite number of magnetic tape media can be used repeatedly, but when restoring a past disk image, it is limited to a relatively new image. However, a general system is characterized in that it can be a sufficiently realistic solution, and that it can reduce off-line operations such as adding new media and storing ejected media. If it is desired to widen the restorable time range, it can be adjusted by increasing the number of turns of the medium operated between the drive device 11 and the drive device 12.

(Sixth Embodiment) FIG. 7 is a diagram showing a configuration of a backup system according to a sixth embodiment of the present invention. In the sixth embodiment, a mode including system operation will be described based on the basic principle of the backup device described above.

In FIG. 7, the host computer 1
It is connected to the CSI bus 2, and a disk device or the like is connected to the SCSI bus 2. The magnetic disk device 3 is a data backup target disk, and is connected to the host computer 1 via the SCSI bus 2. Similarly, a magnetic tape controller (backup device controller) 4 is connected to the host computer 1 via the SCSI bus 2. Data is written to and read from the second magnetic disk device 6 via the controller 4.

The autochanger device 10 houses a plurality of drives and a mechanical transport device for magnetic tape media. The magnetic tape drive device 11 is housed in the autochanger device 10 and is under the control of the controller 4. The second magnetic tape controller (backup device controller) 21 can operate independently of the host computer 1.

The second magnetic tape drive 12, the third
The magnetic tape drive device 13 and the fourth magnetic tape drive device 15 are housed in the autochanger device 10 and are under the control of the second magnetic tape controller 21. The magnetic tape medium 14 is used for the autochanger 10.
Used repeatedly within.

The configuration example shown in FIG. 7 is an extension of the configuration example shown in FIG. 6, and basically operates based on the basic principle shown in FIG. A disk write operation from the host computer 1 to the magnetic disk device 3 is recorded on a medium set in the drive device 11. After recording a certain amount of operations or after a certain period of time, the recorded media is stored in the autochanger device 1.
0 and is set in the drive device 12.

In the initial state, the medium on which the initial image of the magnetic disk device 3 is recorded is set in the drive device 13, and the second magnetic tape controller 21 is recorded on the medium set in the drive device 12. The latest disk image is generated based on the operation and the disk image recorded on the medium set in the drive device 13, and the drive device 1
5 is stored in the new medium.

Thereafter, the old disk image medium set in the drive device 13 is ejected from the autochanger device 10, and the new disk image medium set in the drive device 15 is moved to the drive device 13. A new medium stocked inside the autochanger device 10 is set in the drive device 15. The medium on which the operation is recorded is transported to the drive device 11 and used repeatedly. In order to continuously record the disk write operation, at least two media used between the drive device 11 and the drive device 12 should be prepared.

In the configuration example shown in FIG. 7, if the ejected disk image media is stored, it is possible to restore the past disk image, albeit in stages, and to achieve high-speed data restoration. Become. Further, by increasing the number of turns of the medium operated between the drive device 11 and the drive device 12, it is possible to adjust the time range in which the disk image can be restored at an arbitrary timing.

(Modification of Fourth, Fourth, Fifth, and Sixth Embodiments) The magnetic disk device 6 for the write buffer
Buffer storage using a VRAM may be used. When a magnetic disk device is used, a single drive, a RAID device, or a semiconductor disk device may be used.

In particular, in the configurations shown in FIGS. 5 and 6, the drive device 13 may be a fixed magnetic disk device or a semiconductor disk device. 5 to 7 show an example in which the magnetic tape controller 4 snoops the SCSI bus 2. However, if the same operation as that for the disk device to be backed up can be actually obtained, the same SCSI bus is used. The point that you do not need to use,
This is the same as in FIG.

It should be noted that the present invention is not limited to only the above embodiments, and can be carried out with appropriate modifications without departing from the scope of the invention. In each of the above embodiments, devices and interfaces are limited for the sake of simplicity, but other devices and interfaces may be actually used. For example, SCSI
The bus 2 may be a fiber channel, IEEE 1394, or IDE. The magnetic disk device 3 may be a single drive, a RAID device, or a semiconductor disk device. The backup medium may be a removable magnetic disk, a magneto-optical disk, or a rewritable optical disk.

[0068]

According to the present invention, it is possible to provide a backup device which allows online backup of storage data and does not degrade system performance even during backup. Further, according to the backup device, storage data at any time in the past can be restored, and not only a failure in the storage device itself to be backed up, but also a software failure on the host computer or data corruption due to an operation error by an operator. Sometimes, data can be restored.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a backup device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an operation procedure of the backup device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a configuration and an operation procedure of a backup device according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a configuration and an operation procedure of a backup device according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a backup system according to a fourth embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a backup system according to a fifth embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a backup system according to a sixth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 host computer 2 SCSI bus 3 magnetic disk device 4 magnetic tape controller 5 magnetic tape medium 6 second magnetic disk device 7 third magnetic disk device 10 autochanger device 11 magnetic tape drive device 12 ... second magnetic tape drive 13 ... third magnetic tape drive 14 ... magnetic tape media 21 ... second magnetic tape controller

Claims (4)

[Claims] 1. A backup device for backing up data in a storage unit connected to a host computer via an input / output interface, wherein the backup device is connected to the host computer via the same or different input / output interface as the input / output interface. A controller unit; and a secondary storage unit connected to the controller unit. The controller unit monitors an operation flowing on the input / output interface, and when it is a write instruction to the storage unit. A backup device for controlling the write operation to be recorded in the secondary storage unit. 2. The backup device according to claim 1, wherein the controller unit includes a buffer storage unit that can be accessed at a higher speed than the secondary storage unit. 3. The apparatus according to claim 1, further comprising a plurality of buffer storage units, wherein the plurality of buffer storage units are individually used for capturing a write operation to the storage unit, and when recording the operation in the secondary storage unit, 3. The backup device according to claim 2, wherein control is performed so as to refer to the buffer storage unit. 4. The secondary storage unit comprises a device using a replaceable medium, wherein the secondary storage unit and the medium are housed in an autochanger, and the autochanger is controlled to exchange the medium. A second secondary recording unit that can use the same medium as the secondary storage unit, and a third storage unit that stores an initial image of the storage unit in an initial state.
The second secondary storage unit and the third secondary storage unit are connected to a second controller unit that can operate independently of the controller unit. The medium recorded in the secondary storage unit is transported to the second secondary storage unit via the autochanger, and the second controller unit is configured to store the storage medium via the second secondary storage unit. 4. The method according to claim 1, wherein the contents of the third secondary storage unit are updated to match the contents of the latest storage unit by referring to a write operation to the unit. Backup device.