JP2011076175A - Storage device and data deletion method for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a time to be spent in performing overwrite deletion of recorded data. <P>SOLUTION: A disk array device 2 includes: a hard disk drive unit 25 in which RAID(Redundant Arrays of Inexpensive Disks) for redundantly recording data by using a parity are configured; a data processing unit 22A for, when receiving instructions to record data in the hard disk drive unit 25, redundantly recording the data in the hard disk drive unit 25; a data generation unit 22B for, when receiving instructions to perform the overwrite deletion of the data recorded in the hard disk drive unit 25, generating the data of the random pattern; and an overwrite processing unit 22C for generating the data of the random pattern, and for reading the storage place of the data excluding the parity recorded in the hard disk drive unit 25, and for performing overwrite deletion processing by using the data of the random pattern with respect to the read storage place of the data. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a storage apparatus configured to be able to erase recorded data and a data erasing method of the storage apparatus.

  A technology is known that increases the reliability of data storage by configuring RAID (Redundant Arrays of Inexpensive (or Independent) Disks) using a plurality of hard disk drives mounted in a storage device such as a disk array device. .

  When updating data recorded in such a storage device configured with RAID, for example, when performing write processing of a small block of about 4 kilobytes, the data to be updated and the parity before update are recorded. A procedure is required in which the update parity is created based on the data to be updated, the data to be updated, the parity before the update, and the data after the update, and then writing the update data and the update parity to the recording unit.

  Even when data recorded in such a storage device is overwritten and erased using, for example, random number data, it is necessary to perform a parity update process in the same manner as the above-described data update.

  As a technology related to the technology for erasing data recorded in the storage device, a technology for erasing specific data recorded in the hard disk drive using random number data generated by the hard disk controller in the storage device. (See, for example, Patent Document 1), a technology for controlling the erasure of a specific area of the storage space of a storage device without introducing a complete erase command and requiring data transfer from the host to the storage device (eg, Patent Document 2) is known. Furthermore, in a RAID configuration having parity, a technique (for example, see Patent Document 3) that can identify a unit that stores data and a unit that stores parity by identification information is known.

JP 2006-031268 A JP 2007-011522 A JP 2008-198049 A

  At the time of disposal of a storage apparatus configured with RAID, for example, all data recorded in the storage apparatus is generally erased for the purpose of preventing information leakage. As a data erasing method, the first method of electrically and magnetically filling the hard disk drive in the storage device, or the second method of physically destroying the hard disk drive, and overwriting the data recorded on the hard disk drive A third method of erasing can be considered.

  Of these, the third method is the most realistic in terms of work environment and cost effectiveness.

  However, when all the data is overwritten and erased by the third method, there is a problem that it takes time for the erasing process.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a storage apparatus and a data erasing method for the storage apparatus that can reduce the time spent when overwriting and erasing recorded data. There is.

  In the storage device, when a storage unit configured to record data redundantly using parity and having received an instruction to record data in the recording unit, the storage device receives the instruction to record the data on the recording unit based on the instruction. When receiving a data processing unit that records data redundantly, and an instruction to overwrite and erase the data recorded in the recording unit, a data generation unit that generates random pattern data, and the data generation unit After the data is generated, an overwrite process is performed to read the data storage location except for the parity recorded in the recording unit, and to perform the process of overwriting and erasing the read data storage location using the random pattern data And a section.

  According to the present invention, it is possible to provide a storage apparatus and a data erasing method for the storage apparatus that can reduce the time spent for overwriting and erasing recorded data.

It is a figure which shows the structure of the storage system in embodiment of this invention. It is a flowchart which shows the overwrite deletion process in the same embodiment. It is a figure for demonstrating the parity and data currently recorded on the hard-disk drive part in the embodiment. It is a figure for demonstrating the state which overwritten and erased the data in FIG.

  FIG. 1 is a diagram showing the configuration of the storage system 100. As shown in FIG. 1, the storage system 100 includes a server 1 that is a host device and a disk array device 2 that is a storage device connected to the server 1.

  The disk array device 2 includes a host director unit 21, a CPU (Central Processing Unit) unit 22, a cache memory unit 23 as a data storage unit, a disk director unit 24, and a hard disk drive (HDD) unit 25 as a recording unit. Is done. The CPU unit 22 is connected to the host director unit 21, the cache memory unit 23, and the disk director unit 24 so as to be able to communicate with each other.

  The server 1 issues various instructions such as an instruction to write data, an instruction to read data, and an instruction to overwrite data to the disk array device 2. When the disk array apparatus 2 receives various instructions issued from the server 1, the disk array apparatus 2 executes processing based on the instructions.

  Next, each part of the disk array device 2 will be described.

  The hard disk drive unit 25 has a plurality of hard disk drives 251, 252, 253,..., And a plurality of hard disk drives 251, 252, 253,. It is configured to record data redundantly.

  When the server 1 issues various instructions to the disk array device 2, the host director unit 21 performs interface processing and transmits data after the interface processing to the CPU unit 22.

  The CPU unit 22 includes a data processing unit 22A, a data generation unit 22B, and an overwrite processing unit 22C.

  When the data processing unit 22A receives an instruction to record data in the hard disk drive unit 25 from the server 1 via the host director unit 21, the data processing unit 22A executes the same data recording process as that of the prior art. That is, the data processing unit 22A reads the data to be updated and the parity before update from the recording unit, and creates the update parity based on the data to be updated, the parity before update, and the data after update. Thereafter, a process of writing the update data and the update parity into the recording unit is executed. By this processing, the data processing unit 22A can record data on the hard disk drive unit 25 redundantly using the parity. However, for example, when the data recorded on the hard disk drive unit 25 of the disk array device 2 is overwritten and erased to prevent information leakage, the data processing unit 22A does not execute the data recording process.

  In this case, instead of the data processing unit 22A, the data generation unit 22B and the overwriting processing unit 22C execute an overwrite erasing process described later.

  The cache memory unit 23 temporarily stores the random pattern data created by the data generation unit 22B.

  Based on an instruction from the data processing unit 22A, the disk director unit 24 reads data and parity recorded in the hard disk drive unit 25, writes data and parity to the hard disk drive unit 25, and overwrite processing unit 22C. Is read from the storage location of the data recorded in the hard disk drive unit 25, and random data is written to the storage location of the data in the hard disk drive unit 25.

  Next, the operation of the storage system 100 will be described. FIG. 2 is a flowchart showing the overwrite erasure process of the storage system 100.

  The server 1 issues an instruction to the disk array device 2 to overwrite all data recorded on the hard disk drive unit 25 with random pattern data (301).

  The host director unit 21 performs interface processing between the server 1 and the disk array device 2 (302). By this processing, an instruction to overwrite all data in the disk array device 2 is received, and an instruction to overwrite all the data is transmitted to the CPU unit 22.

  When the CPU unit 22 receives an instruction to overwrite all data, the data processing unit 22A does not execute the process, and the data generation unit 22B creates random pattern data used when erasing data (303). ).

  The random pattern data created by the data generator 22B of the CPU 22 is temporarily stored in the cache memory 23 (304).

  Next, the overwrite processing unit 22C of the CPU unit 22 reads all the data storage locations excluding the parity from the hard disk drive unit 25 via the disk director unit 24, and applies the cache memory unit to all the read storage locations. The random pattern data temporarily stored in 23 is read and overwritten and erased (305).

  Next, a specific example of the overwriting and erasing process in 305 will be described with reference to FIGS. FIG. 3 is a diagram showing the disk director unit 24 and the hard disk drive unit 25 in FIG. Here, as shown in FIG. 3, in the hard disk drive unit 25, RAID 6 is configured by the hard disk drives 251 to 256, and has a RAID configuration having parity.

  In the hard disk drives 251 to 256, parity (P, Q) and data excluding the parity (D) are recorded.

  When all data recorded on the hard disk drive unit 25 is overwritten and erased using random pattern data, the disk director unit 24 receives a parity (from each of the hard disk drives 251 to 256 based on an instruction from the overwrite processing unit 22C. All the storage locations of data (D) except P, Q) are read, and overwriting erasure with random pattern data is performed on the storage locations of all the read data (D). That is, the random pattern data is written in the data (D) areas of the hard disk drives 251 to 256 of the hard disk drive unit 25, and the data (D) area excluding the parity is overwritten and erased by the random pattern data.

  FIG. 4 shows a state in which all the data except the parity are overwritten and erased by the processing described with reference to FIG. As shown in FIG. 4, all data (D) excluding parity (P, Q) is overwritten and erased from the hard disk drives 251 to 256 of the hard disk drive unit 25 shown in FIG. This is because when all the data recorded in the hard disk drive unit 25 is overwritten and erased, only the data (D) excluding the parity (P, Q) is not executed without recalculating the parity (P, Q). This is because everything is overwritten and erased.

  According to this embodiment, when all data recorded in the hard disk drive unit 25 of the disk array device 2 is overwritten and erased with random pattern data, the disk array device 2 reads the parity before updating, Since the update process and the update parity write process are not performed, the time spent for overwriting and erasing all data recorded in the hard disk drive unit 25 can be reduced.

  For this reason, for example, when the disk array device 2 is discarded, all data recorded in the hard disk drive unit 25 is erased by overwriting with random pattern data to prevent information leakage. It can be performed in a short time as compared.

  In addition, the creation of random pattern data to be overwritten when erasing all data recorded in the hard disk drive unit 25 is not performed by the server 1 but by the data generation unit 22B of the disk array device 2. The load on the server 1 when data is overwritten and erased can be reduced.

  In the above embodiment, the case where RAID 6 is applied to the hard disk drive unit 25 has been described. However, the present invention is not limited to this, and a RAID having a parity even in RAIDs other than RAID 6 is a hard disk drive unit. It can be applied to the case of 25.

  In the above embodiment, the case where all data recorded on the hard disk drive unit 25 is erased due to information leakage has been described. However, the present invention is recorded on the hard disk drive unit 25 regardless of the purpose of erasure. The present invention can be applied to the case of erasing all existing data.

  Furthermore, in the above-described embodiment, the case has been described in which the entire area of the data (D) recorded in the hard disk drive unit 25 is overwritten and erased according to the overwriting and erasing instruction. However, the present invention is not limited to this. In addition, even when erasing an area of a part of the data recorded in the hard disk drive unit 25 (for example, one RAID group when a plurality of RAID groups are configured in the hard disk drive unit 25). Can be applied.

  The present invention can be used for a storage apparatus for overwriting and erasing data and a data erasing method of the storage apparatus.

DESCRIPTION OF SYMBOLS 1 ... Server 2 ... Storage device 21 ... Host director part 22 ... CPU part 22A ... Data processing part 22B ... Data generation part 22C ... Overwrite processing part 23 ... Cache memory Unit 24... Disk director unit 25... Hard disk drive unit 100 .. storage systems 251 to 256... Hard disk drive P, Q.

Claims (6)

A recording unit configured with RAID for redundantly recording data using parity; and
When receiving an instruction to record data in the recording unit, a data processing unit that redundantly records the data in the recording unit based on the instruction;
When receiving an instruction to overwrite and erase the data recorded in the recording unit, a data generation unit for generating random pattern data;
After the random pattern data is generated by the data generation unit, the storage location of data excluding the parity recorded in the recording unit is read, and the random pattern data is used for the storage location of the read data An overwrite processing unit for overwriting and erasing,
A storage device comprising: The instruction to overwrite is received from a higher-level device configured to be able to communicate with the storage device;
The storage apparatus according to claim 1. The data generation unit generates the data of the random pattern at a timing when the instruction to overwrite is received;
The storage apparatus according to claim 2. A data storage unit that temporarily stores data of the random pattern generated by the data generation unit;
The overwrite processing unit performs the overwrite erasing process using the random pattern data temporarily stored in the data storage unit;
The storage apparatus according to claim 3. The instruction to overwrite and erase is an instruction to overwrite and erase all data recorded in the recording unit,
The storage apparatus according to any one of claims 1 to 4, wherein: A recording unit configured to record data redundantly using parity; and when receiving an instruction to record data in the recording unit, the data is redundantly recorded in the recording unit based on the instruction A storage device data erasing method comprising:
When receiving an instruction to overwrite the data recorded in the recording unit, generating a random pattern data; and
After generating the random pattern data, the storage location of the data excluding the parity recorded in the recording unit is read, and the storage location of the read data is overwritten and erased using the random pattern data The steps of
Data erasing method for storage apparatus having

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