JPS58166472A - Doubling system of journal collecting magnetic tape device - Google Patents

Abstract

PURPOSE:To utilize magnetic tape device by using two out of three magnetic tape devices as an original and a duplicate in-use device and the remaining one for switching, and using the device for switching as an in-use device when switching due to a fault is required. CONSTITUTION:Two out of three magnetic tape (MT) devices 1-3, i.e. MT devices 1 and 2 are used as the original and duplicate in-use devices and the remaining MT device 3 is used as the device for switching. Then when the MT device 2 need be switched owing to a fault, etc., switching from the MT device 2 to the MT device 3 is performed to regard the MT device 3 as the duplicate in- use device. When the MT device as the original in-use device need be switched, switching from the MT device 1 to the MT device 2 is performed to use the MT device 2 as the original in-use device. Thus, the MT devices are switched one by one, so two in-use devices are backed up securely by one device for switching.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a duplex system for journal collection MT in which journal information collection in an online system is performed using xMT (magnetic tape) devices that are dual-duplexed as primary and secondary.

[Prior art and problems]

Data conflict-based recovery *a Generally consists of a total dump, which is a complete copy of the data base, and journal data such as pre-update information and post-update information for database update data. In online systems, the creation of various materials and the source/disaster recovery
A journal file serving as data is provided on, for example, a high-speed, high-density MT (magnetic tape) i&oki. This file is important, so double
It has a 7-isle configuration. Therefore, even if one of them becomes a failure, online operation can continue. Conventionally, when duplicating journal collection MT devices in an online system, two switching devices were also provided for two active devices, for a total of four devices. This switching device is used as a backup for the current device, and if a failure occurs in the current device or other switching conditions occur in the current device, two of the current devices are simultaneously switched to the switching device. However, if the number of MT devices in the entire system is small, using four MT devices as companions to the journal collection MT device will limit the execution of other tasks. Moreover, it is easy and simple to switch two devices at the same time when a switching condition occurs in the current device.

In reality, it is highly unlikely that a failure or other switching condition will occur in two devices at the same time.

[Purpose of the invention]

In view of the above points, the present invention provides a duplication method for journal collection MT in an online system using a small number of MT devices, and provides a journal collection method that can effectively utilize MTifi without reducing the reliability of the online Φ system. [Structure of the Invention] In order to achieve the above object, the duplication method of the journal collection magnetic tape device of the present invention is designed to provide a duplex system for collecting MT, which is capable of duplicating the collection of the same journal information. In a duplexing method for a journal collection magnetic tape device that writes to a sub-duplicated magnetic tape device, three magnetic tape devices are provided, and two of the three magnetic tape devices are The remaining magnetic tape device is used as a primary and secondary active device, and the remaining magnetic tape device is used as a switching device for the primary and secondary active devices, and if the magnetic tape device as the active device encounters a switching condition such as a failure or the end of the medium. If this occurs, the switching device is used as the current IjjtrIIt.

[Embodiments of the invention]

Hereinafter, the present invention will be explained with reference to the drawings.

Figure w41 is a diagram showing an overview of the operation of the duplex system of the journal collecting magnetic tape device according to the present invention, Figure 2 is a functional block diagram showing an embodiment of the present invention, and Figure 3 is a processing diagram of an embodiment of the present invention. FIG. 4 is a flow chart explaining EOV/error processing applied to the present invention.

FIG. 5 is a flow chart explaining the operator standby machine registration process applied to the present invention, and FIG. 6 is a flow chart explaining the operator switching instruction process applied to the present invention. It means op volume.

In the figure, 1.2 and 3 are journal collection MT devices, 4
is the journal MT access processing unit, 5 is the journal MT
A primary and secondary management section, 6 a journal MT switching processing section, and 7 an operator console.

The duplication method of journal collection MT according to the present invention is as follows:
As shown in the figure, the journal collecting MT device 1, 2 and 3 are configured, and the number of journal collecting MT #c units is reduced by one compared to the conventional system. Journal collection*MT device consisting of three units 1.2 and 3
In this case, two devices are used as active devices and one device is used as a switching device. Then, when a switching condition such as a failure or the end of the medium occurs, or according to instructions based on the operator's judgment, switching is performed for any one of the dust removal devices as appropriate. This will be explained in chronological order using FIG. 1 as an example. #I
In Figure 1, the vertical direction shows the passage of time. Now T
At time o, journal collection MT device 1 is the primary active device, journal collection MT device fi! i2 is the secondary active device,
Assume that journal collection MT device &3 is the switching device.

If a failure or other switching condition occurs in the journal collection MT device fll12 at the time of TI.

Journal collection GMT! Switching from 112 to 3 is performed, and the journal collection MT device y! 1.3 becomes the secondary active device. Next, when a switching condition occurs in the journal collection MT device ml, which is the positive active device, at time T2, the journal collection M
Switching from T device 1 to 2 is performed, and now journal collection MT! 112 is the positive active device. Similarly, at time Tm and time T4, switching is performed from the journal collection MT device in which the switching condition has occurred to the journal collection MT device in the standby state for switching. Switching conditions include detection of EOV, occurrence of an error, operator instructions, and the like. Errors include device errors and media errors. In this way, the journal collection MT system is always switched one by one, so only one machine can be switched and cleaved! lit is sufficient to ensure backup of the two active devices.

An embodiment of the present invention is shown in a functional block diagram as shown in FIG. 2. The journal MT access processing unit 4 requests the journal MT primary and secondary management s5 to notify the journal MT primary and secondary machine numbers, and accesses the journal M according to the machine number notification.
Write journal information to T, write E to Maku
The next time a medium end condition of OV% or an error occurs, a journal MT switching request is sent to the journal MT switching processing unit 6. The journal MT primary and secondary management unit 5 notifies the machine number of the primary or secondary journal MT according to the request from the journal MT access processing unit 4, and then
According to the tr momentum notification from the switching processing unit 6, the journal M
Change the primary or secondary machine number of T. The journal MT switching processing unit 6 prepares a spare machine according to the instruction to register a spare machine number from the operator console 7, and uses the registered spare machine number as a new machine number in response to a switching request from the journal MT access outside 1. Notify the journal MT primary and secondary management department. Further, in response to a switching instruction from the operator console 7, the journal MT switching processing unit 6 notifies the journal MT regular management fls5V of the registered spare machine number as a new machine number. The operator console 7 notifies the operator of an error, and sends an instruction from the operator to register a spare machine number and a switching instruction to the journal MT switching system s6.

Next, we will discuss the specific processing iMnK in the example in the third section.
This will be explained with reference to the figures. First, when attempting to write a journal, ■ Request notification of the correct number, and move on to process ■.

■According to the notification from Seishin Homare, journal information is written to Seisoban's journal MT, and the process moves to ■.

■ Check whether EOV has occurred.

If No, proceed to the process of KFi (%). If Ys-, proceed to the process of (2).

■ Check if an error has occurred.

In the case of No, the process moves to ■, and in the case of 7 days, the process moves to ■.

■ Perform EOV processing and move on to process (■).

■ Execute the error stone block and return to the process of ■.

■ Request notification of the sub-machine number and move on to process ■.

■According to the notification from the sub-machine number, write journal information to the journal MT of the sub-machine number, and move on to process (■).

■ Check whether EOV has occurred.

If No, move on to ■ process *If Yaa, proceed to ■
Move on to processing.

[F] Check whether an error has occurred. If ONo, the process ends, and if hYa-, the process moves to @.

(Ill Perform EOV processing and end.

■ Perform error handling and return to process ■.

If an EOV occurs and a 2- or 2- match occurs, the process shown in FIG. 4 is performed.

Next, FIG. 4 will be explained.

0 Perform post-processing of the corresponding journal MT.

Move on to the process of ■.

■ Check whether the pre-registered items are available.

If there is no, move on to [phase] processing, and if there is, proceed to [phase]
Move on to processing.

Q: Issue a request to the operator for instructions on the spare machine.

[Co., Ltd.] Make it a spare machine and use it as a working machine, and move on to @ processing.

@ [Phase] processing has made it into a working machine - perform opening processing for the journal MT, and make it ready for loading into this working machine.

Spare aircraft registration is not necessarily something that is always done.
As shown in Figure 5, it is left to the operator's discretion.
The registration is performed when the operator notifies that the spare machine is ready.

The process of switching the primary and standby machine to the active machine is performed not only in the case shown in Figure #I4, but also in response to an operator's switching instruction, as shown in Figure 6.

Next, the processing will be explained.

[Phase] Check if there is a spare machine.

If there is no, the process goes to KFi 2-, and if there is, the process moves to (2).

0 Perform post-processing of the current machine and move on to QD processing.

■ Perform the process of switching the standby machine to the active machine and move on to the @ process.

@ Performs opening processing for the journal MT that has become a working machine by the @ process, and makes it possible to write to this working machine.

Through the above processing, the operator gives a switching instruction to make the standby machine the working machine, and the processing in the next case is completed.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to realize a duplex journal collection MT system using three MT devices, one less than the conventional four MT devices. Moreover, since the desk device uses the same two MT devices as before, it can be operated without reducing the reliability of the online system, and the effective use of MTIiic & can be expected. .

[Brief explanation of drawings]

FIG. 1 is a diagram showing an overview of the operation of a duplex system for a journal collection magnetic tape device according to the present invention, and FIG. 2 is a diagram showing an embodiment of the present invention. ! Fig. 3 is a flowchart explaining the processing flow of an embodiment of the present invention;
FIG. 5 is a flow chart illustrating the EOV/error processing applied to the present invention; FIG.
The figure is a flowchart illustrating four operator switching instruction processes according to the present invention. Note that EOV is engineering/de-
It means op volume. 1.2 and 3... Journal collection MT device, 4... Journal MT access processing unit, 5... Journal MT
Positive-11i buried section, 6... Journal MT switching processing section. 7...Operator processing section. Patent consultant, Fujitsu Co., Ltd. Attorney, Kyotani Yobuhi 1 Figure X3 Figure 4 Return Ladder Figure X6 End

Claims (1)

[Claims] In a duplex system for journal collection magnetic tape devices, where the same journal information is collected and written to the primary and secondary magnetic tape devices, three magnetic tape RI devices are installed, and #3 magnetic tape Two of the magnetic tape devices are used as primary and secondary active devices, and the remaining magnetic tape device is used as a switching device for the above-mentioned primary and secondary active devices. A duplex system for a journal collection magnetic tape device, characterized in that when a switching condition such as a failure or the end of a medium occurs in the magnetic tape device, the switching device is used as the active device.