JPH103361A - Data backup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data backup device with which the large capacitance of data can be backed up at high speed, the detection or correction of data error on a data transfer path is enabled and further, data erasure caused by the hit of power source can be prevented. SOLUTION: A data backup device 10 is constituted while having a buffer memory 4, tape drive 5 and RAID control part 13 or the like. Backup data from a host computer H are temporarily stored through an SCSI bus 11, SCSI controller 12 and buffer memory 4 into a high-speed storage device 14 of the RAID control part 1. The high-speed storage device 14 can transmit data at higher speed than the tape drive 5 and the temporarily stored data are stored through the buffer memory 4 into the tape drive 5 after the completion of temporary storage of the data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data backup device for backing up data for a file system such as a server device in an external storage device such as a magnetic tape.

[0002]

2. Description of the Related Art For example, in a bank or securities company, while operating a file system such as a server device, online data is destroyed for some reason or an important hard disk in the file system breaks down. Failure may occur.

In such a case, even if a file system such as a server device is restored, business cannot be continued immediately because correct online data has been lost. Therefore, generally, these online data are regularly backed up using a data backup device. As such a data backup device, a magnetic tape device using a magnetic tape (for example, SMT, CMT,
CGMT, DAT, DLT) are widely used.

FIG. 6 shows a conventional data backup device 1.
(Conventional example 1) is shown. The data backup device 1 transfers data from a host computer (host machine) H to a tape drive 5 via a buffer memory 4.
Back up to the magnetic tape attached to the
The configuration is such that restoration is performed from the magnetic tape to the host computer H via the buffer memory 4. The connection between the host computer H and the data backup device 1 is performed, for example, via the SCSI controller 3, and the data transfer rate is, for example, 8 MB and 5 MB / S.

The writing and reading of data to and from the magnetic tape of the tape drive 5 is performed by the DMAC 6 using a DMA (Direct Memory Access) method. The I / O processor 7 controls the operation of writing and reading the DMAC 6 to and from the tape drive 5 based on the information in the local memory 8 and controls the operation of connecting and disconnecting the SCSI controller (SSCSI) 3 to and from the host computer H. By providing the buffer memory 4 for temporarily storing data, data transfer between the host computer H and the buffer memory 4 or between the buffer memory 4 and the tape drive 5 can be performed asynchronously. it can.

There is also a technique disclosed in, for example, Japanese Patent Application Laid-Open No. 4-124721 (conventional example 2). Conventional example 2
Then, at the time of backup, a series of sequential data transferred from the host computer is temporarily stored in a buffer memory, and this data is divided into units (data blocks) of a predetermined data amount, and these data blocks are divided into a plurality of data blocks. The data is transferred and recorded on a magnetic tape in parallel. Also, at the time of restoration, these data blocks are read simultaneously from a plurality of magnetic tapes in parallel and recorded in the buffer memory, and the data blocks recorded in the buffer memory are transferred in the same order as when transferred from the host computer. And the combined data is transferred to the host computer.

[0007]

However, the above prior art has the following problems. That is, in the case of the conventional example 1, since the data transfer speed at the time of reading and writing to and from the magnetic tape in the tape drive is low, the processing time for backup and restoration takes a long time.

In the case of the conventional example 2, the data transfer speed at the time of reading and writing can be increased as compared with the conventional example 1. However, the amount of data exchanged between the host computer and the buffer memory or between the buffer memory and the tape drive is large and exceeds the storage capacity of the buffer memory (that is, the buffer memory becomes full). In such a case, the data transfer process between the host computer and the buffer memory may be temporarily stopped. In addition, since a series of data is divided and recorded and stored on a plurality of magnetic tapes, it is necessary to store a plurality of magnetic tapes for one data, and the handling is complicated. In addition, since the number of tape drives and magnetic tapes to be handled is increased, there is a problem that an installation space, a storage space, and an extra space are required.

In addition, in each of the conventional examples, even if data is garbled in the data transfer path between the host computer and the buffer memory or between the buffer memory and the tape drive, it cannot be detected or repaired. . Furthermore, if the power supply is momentarily cut off during data backup or restoration, the contents of the buffer memory or information on the progress of the backup or restoration will be lost. There is also the problem of having to start over.

[0010] It is an object of the present invention to provide a data backup device which can back up a large amount of data at high speed, detect and repair a data error in a data transfer path, and prevent data loss due to a momentary power interruption. It is in.

[0011]

A data backup device according to the present invention comprises: first storage means for storing data from a host computer in a storage medium and restoring the stored data to the host computer; A second storage unit for temporarily storing data from the buffer unit and having a higher data transfer rate than the first storage unit, wherein the first storage unit is configured to store the data Data from a host computer is temporarily stored, and the temporarily stored data is transferred to the first storage means. With this configuration, data from the host computer can be backed up at high speed.

Preferably, the data backup device comprises a host computer, a first storage means, and a second storage means.
2. The data backup device according to claim 1, further comprising buffer means for temporarily storing data transmitted to and received from said storage means. With this configuration, data transfer between the host computer and the buffer unit and between the buffer unit and the first and second storage units can be performed asynchronously.

Further, the second storage means preferably comprises:
Data from the host computer is stored with redundancy. With this configuration, a data transmission error at the time of backup can be repaired. As a specific example of such a configuration, for example, a RAID (Redundan
t Arrays Independent Disk
s) Recording data by control.

[0014] Preferably, the second storage means detects a transmission error in data from the host computer. With this configuration, a data transmission error at the time of backup can be detected. As a specific configuration example for this, SCS is stored in the second storage means.
An I interface may be provided to transmit data from a host computer via the I interface.

Further, in the present invention, when data transfer from the host computer to the second storage means is completed, the interface with the host computer is disconnected. More specifically, a magnetic tape device can be used as the first recording means, and a hard disk or a semiconductor disk can be used as the second storage means. Further, it is preferable to further provide a power supply backup means for the first and second storage means, thereby preventing data loss due to an instantaneous interruption of the power supply.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a data backup device according to the present invention will be described below. FIG. 1 is a diagram illustrating a configuration example of a system including the data backup device 10 and a host computer H.

The data backup device 10 is a SCSI
Controller 12, buffer memory 4, tape drive 5, DMAC (Direct Memory Access)
ssController) 6, I / O processor 7,
It comprises a local memory 8, a RAID controller 13, an uninterruptible power supply 16, and the like. In addition, RAID (R
edundant Arrays of Indepe
The ND (disks) control unit 13 includes a SCSI controller 15 and a high-speed storage device 14. The uninterruptible power supply 16 is connected to prevent an instantaneous interruption of power during operation of the high-speed storage device 14 or the tape drive 5.

Here, the backup data transferred from the host computer H is, for example, 20 bits with a width of 16 bits.
The data is input to the data backup device 10 through the SCSI bus 11, which is an MB / S. This SCSI bus 11
Interface with the data backup device 10
Is controlled by the SCSI controller 12. The buffer memory 4 is for temporarily storing data during a backup or restore operation. Then, via the buffer memory 4, RA
Data transfer between the ID control unit 13 and the tape drive 5 is performed.

In the RAID control unit 13, the high-speed storage device 14 stores data in order instead of the allowable amount of data in the buffer memory 4 so as not to exceed the allowable amount.
The SCSI controller 15 sets the high-speed storage device 14 to R.
AID control is performed. As the high-speed storage device 14, a storage device that can read and write data at a higher speed than the tape drive 5, such as a hard disk or a semiconductor disk, is used. Here, the data transferred from the buffer memory 4 to the high-speed storage device 14 is, for example, 8
The data is transferred at a speed of 10 MB / S by a bus having a bit width. The capacity of the high-speed storage device 14 is determined in accordance with the amount of backup data. However, if necessary, for example, up to seven hard disks can be added.

The data backup device 10 of the present embodiment
Will be described with reference to FIG. That is, in this case, first, the data transmitted from the host computer H via the SCSI bus 11
The data is stored in the buffer memory 4 under the control of the controller 12 ((1) in FIG. 2). At this time, the data is SCS
Since the I bus 11 is 16 bits wide, the maximum transfer speed is 20 MB / S. Further, the data in the buffer memory 4 is temporarily transferred to the RAID control unit 13 sequentially so as not to exceed the allowable amount of data in the buffer memory 4 ((2)).

The RAID controller 13 stores data in the high-speed storage device 14 under the RAID control of the SCSI controller 15. When the data transfer to the high-speed storage device 14 is completed, the host computer H is notified of the completion of the data transfer, and the connection with the host computer H is cut off by the SCSI controller 12 ((3)). Thereafter, data is transferred from the high-speed storage device 14 to the tape drive 5 via the buffer memory 4,
The data is recorded on the magnetic tape mounted thereon, and the backup operation is completed ((4)). If an unrecoverable failure occurs during the transfer of data from the RAID control unit 13 to the tape drive 5, a request is made to the host computer H to reconnect and retransmit the data in order to perform the backup operation again. Run.

A restore operation in the data backup device 10 according to this embodiment will be described with reference to FIG. That is, first, a command to read data from the magnetic tape mounted on the tape drive 5 is generated from the host computer H. In this case, the SCSI controller 1
2 cannot respond to this immediately, so disconnect the interface once. Next, the tape drive 5 operates to read the data recorded on the magnetic tape and write it to the buffer memory 4 ((2)). This data is temporarily transferred to the high-speed storage device 14 via the SCSI controller 15 of the RAID control unit 13 ((3)).

Next, the I / O processor 7 requests the host computer H to connect the interface via the SCSI controller 12 and the high-speed storage device 14.
, The transfer of data to the buffer memory 4 starts ((4)). Then, data is transferred from the buffer memory 4 to the host computer H via the SCSI controller 12 so that the buffer memory 4 does not become full, that is, the buffer memory 4 does not become full, and the restore operation is completed ( Fifth step (5)).

At the time of the above-mentioned backup and restoration work, the RAID control unit 13
An operation of storing data in the high-speed storage device 14 is performed according to the D level. The RAID control unit 13 can operate in three modes of the normal mode, the degenerate mode, and the recovery mode in either the mirroring scheme or the distributed parity scheme.

For example, in the case of the mirroring system, in the normal mode, data is read from the data disk 14a and is read out from the data disk 14a as shown in FIG.
And write to the shadow disk 14b. In the degraded mode, data is read from the non-failed disk 14b (14a) and the data is read from the non-failed disk 14b (14a).
Write to a). In the recovery mode, data is read from the non-failed disk 14b and written to the failed data disk 14a or shadow disk 14b.

Further, in the case of the distributed parity system, in the normal mode, as shown in FIG.
The data is read from 4p and written to another user disk 14q and parity disk 14r. Also,
In the degenerate mode, data is read from the user disk (excluding the failed disk) 14q and the parity disk 14r, and the user disk (excluding the failed disk) 14q is read.
And writes it to the parity disk 14r. Further, in the repair mode, data is read from the user disk 14q (excluding the replaced disk) and the parity disk 14r, and written to the user disk 14a (including the replaced disk) and the parity disk 14r. As described above, the disk (high-speed storage device 1)
The reliability of the data in 4) is improved. In either case, even if one disk fails, the data disk can be repaired without losing data.

That is, when RAID control is performed by the SCSI controller 15 in a mirroring system, the high-speed storage device 14 includes, for example, two hard disks and semiconductor disks, one of which is a data disk 14a and the other is a shadow disk 14b. Then, the same data as that of the data disk 14a is stored in the shadow disk 14b.

When RAID control is performed by the distributed parity system, the high-speed storage device 14 includes, for example, three hard disks and semiconductor disks, which are respectively configured as data disks 15p and 15q and a parity disk 15r. Data a, b, c, d and parity a ', b',
c ′ and d ′ are stored in a distributed manner. Here, the parities a ′, b ′, c ′, and d ′ are generated by taking the exclusive OR of two data. Then, each data can be determined from the mutual relationship between two data and one parity.

[0029]

As is apparent from the above description, according to the present invention, large-capacity data can be backed up at high speed, and data errors can be detected and repaired on the data transfer path. A data backup device capable of preventing data loss due to interruption can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a data backup device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a flow of data at the time of backup in the data backup device of FIG. 1;

FIG. 3 is an explanatory diagram showing a data flow at the time of restoration in the data backup device of FIG. 1;

FIG. 4 is a schematic explanatory diagram showing an example of RAID control.

FIG. 5 is a schematic explanatory diagram showing another example of RAID control.

FIG. 6 is an explanatory diagram of a data backup device according to the related art.

[Explanation of symbols]

 Reference Signs List 5 tape drive 4 buffer memory 10 data backup device 11 SCSI bus 13 RAID controller 14 high-speed storage device 15 SCSI controller 16 uninterruptible power supply H host computer

Claims (8)

[Claims] A first storage unit for storing data from a host computer in a storage medium and restoring the stored data to the host computer; and temporarily storing data from the buffer unit. A second storage unit having a data transfer speed higher than that of the first storage unit, wherein the first storage unit temporarily stores data from the host computer during data backup, A data backup device for transferring stored data to the temporarily stored data to the first storage means. 2. The data backup according to claim 1, further comprising buffer means for temporarily storing data transmitted and received between the host computer and the first storage means and the second storage means. apparatus. 3. The data backup device according to claim 1, wherein said second storage means stores data from said host computer with redundancy. 4. The data backup device according to claim 1, wherein said second storage means detects a transmission error in data from said host computer. 5. An interface according to claim 1, wherein an interface with the host computer is disconnected when data transfer from the host computer to the second storage means is completed. 2. A data backup device according to item 1. 6. The data backup device according to claim 1, wherein the first recording unit is a magnetic tape device. 7. The apparatus according to claim 1, wherein said second storage means is a hard disk or a semiconductor disk.
Item 7. The data backup device according to any one of Items 6 to 6. 8. The data backup device according to claim 1, further comprising a power supply backup unit for said first and second storage units.