JP2010231548A - Disk array device and backup method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disk array device that reduces frequency of reduction in data transfer speed between a host device and the disk array device during battery charging. <P>SOLUTION: The disk array device includes: a cache memory; a backup unit for backing up data held by the cache memory; and a battery for supplying power required for backup operation. A backup operation is performed upon unintended power supply stop, and upon recovery from the power supply stop, a power capacity required for backup operation and a power capacity remaining in the battery are calculated. Whether the power required for backup operation remains in the battery is determined, and if the power required for backup operation remains in the battery, data is transmitted and received to/from the host device by using the cache memory. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a disk array device having a plurality of storage devices and a backup method thereof.

  In general, a disk array device includes a plurality of storage devices that store data, such as magnetic disk devices, and a controller that controls transmission and reception of data between the plurality of magnetic disk devices and a host device such as a computer. In addition, the disk array device includes a cache memory, which is a volatile memory having a higher data writing / reading speed than the magnetic disk device in order to process data transmission / reception with a host device to which the disk array device is connected at high speed. I have.

  During normal operation, the controller uses the cache memory to send and receive data to and from the host device at high speed, and the data held in the cache memory is transferred to the magnetic disk device, which is a non-volatile memory, at the processing timing of its own device. Store.

  In such a disk array device, if an unintended power supply stop (hereinafter referred to as power supply interruption) occurs due to a power failure or the like during operation, data stored only in the cache memory that is not stored in the magnetic disk device is stored. May be lost. Therefore, the disk array device is provided with various means for preventing data loss due to power interruption.

  For example, the disk array device includes a backup unit including a nonvolatile memory for backing up data in the battery and the cache memory. When the power is turned off, the data in the cache memory is transferred to the backup unit by using the battery power by the controller. Save (hereinafter referred to as backup operation), the next time the disk array device is started up (when recovering from a power failure), the data saved in the backup unit is returned to the cache memory to reduce data loss. Yes.

  Although not related to the disk array device, for example, Patent Document 1 describes a method for backing up data stored in a memory included in a computer.

  In the memory backup device described in Patent Document 1, the data in the RAM to be backed up is periodically copied to the SRAM that holds the data by supplying power from the battery. It is described that data backed up in SRAM is returned to RAM.

JP 9-330278 A

  In the disk array device of the background art described above, the battery whose power capacity has been reduced by the backup operation is charged when the disk array device is next powered on.

  Here, in the disk array device of the background art, the battery is fully charged in order to prevent the backup operation from ending in the middle due to insufficient power capacity of the battery when the power is cut off again in a state where the charging is not completed. Until this time, data transmitted from the host device to the disk array device is always stored in the magnetic disk device together with the cache memory, thereby preventing data loss.

  For this reason, the disk array device of the background art always accesses a magnetic disk device whose data writing / reading speed is slower than that of the cache memory while the battery is being charged. Therefore, until the battery is fully charged, There is a problem in that the data transfer speed between the disk array devices decreases.

  The present invention has been made in order to solve the above-described problems of the prior art, and a disk capable of reducing the chance that the data transfer rate between the host device and the disk array device during the charging period of the battery decreases. An object of the present invention is to provide an array device and a backup method thereof.

In order to achieve the above object, a disk array device of the present invention includes a cache memory that is a volatile memory that temporarily holds data transmitted from a host device, and
A storage device that is a non-volatile memory in which data held in the cache memory is stored and data writing / reading speed is slower than the cache memory;
A backup unit comprising a non-volatile memory for backing up data held in the cache memory when an unintended power supply is stopped;
A battery that is charged at the time of power supply and supplies power necessary for a backup operation in which the data stored in the cache memory is stored by the backup unit when an unintended power supply is stopped.
When unintentional power supply is stopped, the backup operation is executed, and when recovering from the power supply stop, the power capacity necessary for the backup operation and the power capacity remaining in the battery are calculated, and the backup is performed on the battery. A controller that determines whether or not a power capacity necessary for operation remains, and if the power capacity necessary for the backup operation remains in the battery, a controller that transmits and receives data to and from the host device using the cache memory; ,
Have

On the other hand, the backup method of the present invention includes a cache memory that is a volatile memory that temporarily holds data transmitted from a host device, and
A storage device that is a non-volatile memory in which data held in the cache memory is stored and data writing / reading speed is slower than the cache memory;
A backup unit comprising a non-volatile memory for backing up data held in the cache memory when an unintended power supply is stopped;
A battery that is charged at the time of power supply and supplies power necessary for a backup operation in which the data stored in the cache memory is stored by the backup unit when an unintended power supply is stopped.
A method for backing up data stored in the cache memory in a disk array device comprising:
When unintentional power supply stop, execute the backup operation to store the data held in the cache memory in the backup unit,
When recovering from the power supply stop,
Calculate the power capacity required for the backup operation and the power capacity remaining in the battery,
Determine whether the battery has the power capacity necessary for the backup operation,
This is a method of transmitting and receiving data to and from the host device using the cache memory when the power capacity necessary for the backup operation remains in the battery.

  According to the present invention, the chance that the data transfer rate between the host device and the disk array device during the charging period of the battery is reduced is reduced.

It is a block diagram which shows the example of 1 structure of the disk array apparatus of this invention.

  Next, the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an example of the configuration of a disk array device according to the present invention.

  As shown in FIG. 1, the disk array device 2 is transmitted from the host device 1 to the disk array device 2 and the controller 21 that controls the transmission / reception of data between the host device 1 and the disk array device and the operation of the disk array device 2. A cache memory 22 that is a volatile memory that temporarily holds the stored data, a backup unit 23 that includes a nonvolatile memory for backing up the data held in the cache memory 22 when the power is unintentionally disconnected, and an unintended power source. The battery 24 supplies power to the controller 21, the cache memory 22 and the backup unit 23 when disconnected, and a magnetic disk device 25 which is a nonvolatile memory in which data transmitted from the host device 1 is stored.

  The controller 21 may be configured by, for example, an LSI (Large Scale Integrated Circuit) having an arithmetic function and a memory function, and stores an A / D converter, a D / A converter, a CPU, and data necessary for the processing of the CPU. The processing device may include a storage device and a recording medium on which a program for causing the CPU to execute a predetermined process is recorded. The recording medium may be a magnetic disk, semiconductor memory, magnetic tape, CD (compact disk) -ROM, DVD (digital versatile disk), or other recording medium. The processing device loads the program recorded on the recording medium into the storage device, and executes processing as the controller 21 by the CPU according to the program.

  It is assumed that the battery 24 is charged with a predetermined power supply voltage output from a power supply device (not shown) when the disk array device 2 is operating (when power is supplied). In addition, the controller 21 constantly monitors the output voltage of the battery 24 and saves the usage history of the battery 24 in a memory (not shown) or the like.

  In such a configuration, the controller 21 performs high-speed data transmission / reception with the host device 1 using the cache memory 22 during normal operation, and the data held in the cache memory 22 is processed at the processing timing of the own device. The data is stored in the magnetic disk device 25 which is a nonvolatile memory.

  When the controller 21 detects the occurrence of an unintended power interruption, the controller 21 stores all the data held in the cache memory 22 in the backup unit 23 so that the data in the cache memory 22 is not lost. Electric power necessary for the backup operation in which the controller 21 stores the data in the cache memory 22 in the backup unit 23 is supplied from the battery 24. It should be noted that the power cut-off supplies a required power to the controller 21, the cache memory 22, the backup unit 23, and the disk device 25 and generates a predetermined power supply voltage (DC voltage) for charging the battery 24 (not shown). It can be detected by measuring the output voltage of the power supply.

  When the disk array device 2 is started next time after an unintentional power failure occurs (at the time of recovery from power failure), the controller 21 first obtains the value of the memory capacity of the cache memory 22 and backs up from that value. Calculate the power capacity required for operation. Further, the controller 21 calculates the power capacity remaining in the battery 24 from the voltage of the battery 24 and its usage history.

  When the power capacity required for the backup operation is smaller than the power capacity remaining in the battery 24, the power capacity required for the backup operation is compared with the power capacity remaining in the battery 24, and stored in the backup unit 23. The returned data is returned to the cache memory 22, and data is transmitted / received to / from the host device 1 at high speed using the cache memory 22 while charging the battery 24. Further, the controller 21 stores the data held in the cache memory 22 in the magnetic disk device 25 which is a nonvolatile memory at the processing timing of the own device.

  On the other hand, when the power capacity required for the backup operation is larger than the power capacity remaining in the battery 24, the controller 21 transmits the data transmitted from the host device 1 to the disk array device 2 in the same manner as the disk array device of the background art. Are always stored in the magnetic disk device 25 together with the cache memory 22 to prevent data loss.

  The operation similar to this background art is necessary until the power capacity of the battery 24 becomes sufficiently large due to the charging operation of the battery 24 started simultaneously with the recovery from the power interruption, for example, the power capacity of the battery 24 is necessary for the backup operation. The process is executed until the power capacity becomes larger than the maximum power capacity or until the battery 24 is fully charged.

  According to the disk array device of the present invention, even when the battery 24 is not fully charged (even if it is not fully charged) at the time of recovery from an unintentional power interruption, the power capacity necessary for the backup operation remains in the battery 24. If so, high-speed data transfer processing between the host device 1 and the disk array device 2 using the cache memory 22 is executed.

  Therefore, the chance that the data transfer rate between the host device 1 and the disk array device 2 during the charging period of the battery 24 is lower than that of the disk array device of the background art.

DESCRIPTION OF SYMBOLS 1 Host apparatus 2 Disk array apparatus 21 Controller 22 Cache memory 23 Backup unit 24 Battery 25 Magnetic disk apparatus

Claims (6)

A cache memory that is a volatile memory that temporarily holds data transmitted from the host device;
A storage device that is a non-volatile memory in which data held in the cache memory is stored and data writing / reading speed is slower than the cache memory;
A backup unit comprising a non-volatile memory for backing up data held in the cache memory when an unintended power supply is stopped;
A battery that is charged at the time of power supply and supplies power necessary for a backup operation in which the data stored in the cache memory is stored by the backup unit when an unintended power supply is stopped.
When the power supply is not intended to be stopped, the backup operation is executed, and at the time of recovery from the power supply stop, the power capacity necessary for the backup operation and the power capacity remaining in the battery are calculated, and the backup is stored in the battery. A controller that determines whether or not a power capacity necessary for operation remains, and if the power capacity necessary for the backup operation remains in the battery, a controller that transmits and receives data to and from the host device using the cache memory; ,
A disk array device. The controller is
When the power capacity necessary for the backup operation does not remain in the battery at the time of recovery from the power supply stop, until the power capacity of the battery becomes larger than the power capacity necessary for the backup operation, The disk array device according to claim 1, wherein the transmitted data is stored in the storage device together with the cache memory. The controller is
When the power supply necessary for the backup operation does not remain in the battery at the time of recovery from the power supply stop, the data transmitted from the host device is stored together with the cache memory until the battery is fully charged. 2. The disk array device according to claim 1, which is also stored in the device. A cache memory that is a volatile memory that temporarily holds data transmitted from the host device;
A storage device that is a non-volatile memory in which data held in the cache memory is stored and data writing / reading speed is slower than the cache memory;
A backup unit comprising a non-volatile memory for backing up data held in the cache memory when an unintended power supply is stopped;
A battery that is charged at the time of power supply and supplies power necessary for a backup operation in which data stored in the cache memory is stored by the backup unit when an unintended power supply is stopped;
A method for backing up data stored in the cache memory in a disk array device comprising:
When unintentional power supply stop, execute the backup operation to store the data held in the cache memory in the backup unit,
When recovering from the power supply stop,
Calculate the power capacity required for the backup operation and the power capacity remaining in the battery,
Determine whether the battery has the power capacity necessary for the backup operation,
A backup method for transmitting and receiving data to and from the host device using the cache memory when the power capacity necessary for the backup operation remains in the battery.   When the power capacity necessary for the backup operation does not remain in the battery at the time of recovery from the power supply stop, until the power capacity of the battery becomes larger than the power capacity necessary for the backup operation, 5. The backup method according to claim 4, wherein the transmitted data is stored in the storage device together with the cache memory.   When the power supply necessary for the backup operation does not remain in the battery at the time of recovery from the power supply stop, the data transmitted from the host device is stored together with the cache memory until the battery is fully charged. 5. The backup method according to claim 4, wherein the backup method is also stored in the apparatus.