摘要:
A response of a disk device during rebuild can be sped up. A disk array control device determines whether or not there is a normal read request during rebuild. If there is a read request during rebuild, data is read by sequentially switching a plurality of disk devices in a certain block size unit lower than a block size in which each disk device reads data during normal read.
摘要:
To provide a staging method capable of detecting an error in data read from a disk device during staging, a disk array control apparatus 100 includes a data read unit 101 for reading data, a first reference data generation unit 102 for generating first reference data from the read data, a second reference data generation unit 103 for similarly generating second reference data, a true-false determination unit 104 for determining whether or not the data read by the data read unit 101 is correct, and a data write unit 105 for writing data to cache memory.
摘要:
In the present invention, for each set of blocks [#(0) to #(N−1)] storing update data, a history block [#(N)] storing an update state value, for example, a generation, time or check code, showing an update state is provided, constituting a set of management data as a check object. When writing update data on a disk, a new update state value is calculated for the same set of management data and stored in memory as update state confirmation value. The new update state value is also set as write data in the history block in the same set of management data, and the entire of the set of management data including update data and update state value are written onto a disk. The history block is read and disk write omissions are detected by comparing the update state value and the update state confirmation value stored in memory.
摘要:
A RAID controller accesses an access request area on logical volumes distributed and stored on a plurality of physical disks according to a disk access request from a host. The controller has a plurality of management modules which are in-charge of plurality of the redundant groups respectively and issuing a logical format request for each area of said logical volume by referring to a management table for managing progress information of the logical format processing. Each management module has a plurality of the management table for being in-charge of said plurality of redundant groups and a queue for queuing the disk access request. The management module, according to the disk access request, judges whether all the access request areas have been logically formatted referring to the management table.
摘要:
A storage controller executes logical format to enable host access to a physical disk, where the logical format of a physical disk is executed without waiting for host access. The storage controller comprises a logical format management module having bit map memory for managing progress information on format processing of a logical volume, and a lower layer module which accesses a physical disk according to the request of the management module. The management module judges whether all the access areas have been formatted referring to the bit map memory, requests the disk access to the lower layer module if judged as formatted, while, issues a logical format processing request before the disk access, queues the disk access request to the queue if not formatted, further searches the unformatted area from the bit map memory, and issues a logical format processing request if no disk access request exists in the queue.
摘要:
A RAID control apparatus comprises at least a cache memory; an update information management table for storing update information; an update information storage unit for storing, in the update information management table, update information by detecting a data update; a reference value generation unit for generating a reference value expressing a load of a write back processing by using a Small Write method and a Read & Bandwidth Write method based on the update information; a write method determination unit for determining a write method according to the reference value and a write unit for carrying out a write processing, in order to provide a write back method for a RAID apparatus capable of improving a processing speed at the time of updating even in the case of including the processing of updating a part of data stripes.
摘要:
A RAID control apparatus comprises at least a cache memory; an update information management table for storing update information; an update information storage unit for storing, in the update information management table, update information by detecting a data update; a reference value generation unit for generating a reference value expressing a load of a write back processing by using a Small Write method and a Read & Bandwidth Write method based on the update information; a write method determination unit for determining a write method according to the reference value and a write unit for carrying out a write processing, in order to provide a write back method for a RAID apparatus capable of improving a processing speed at the time of updating even in the case of including the processing of updating a part of data stripes.
摘要:
When a write-back request for writing back new data in a cache memory to disk devices forming a redundant configuration of RAID is generated, a write-back processing unit, reserves a parity buffer area in the cache memory, generates new parity, and then, writes the new data and the new parity to the corresponding disk devices. When an error in which the consistency of RAID is broken occurs in a plurality of the disk devices upon write performed by the write-back processing unit, a recovery processing unit reserves, in the cache memory, a cache stripe area storing data of the entire stripe including the new data which is to be written back, and causes the cache control unit to manage it.
摘要:
A RAID apparatus that at least duplicates identical data to store thus duplicated data, which, when an instruction of writing data is given, writes data to a local cache and to a mirror cache, and writes data of the local cache to a primary disk and writes data of the mirror cache to a secondary disk. When an instruction of reading out data is given, and specified data is retained in the caches, the RAID apparatus outputs valid data of the local cache or the mirror cache, while when specified data is not retained in the caches, the RAID apparatus outputs valid data of the primary disk or the secondary disk.
摘要:
In a system for dispersively storing data and parity in a plurality of storage devices, information in a first storage device is restored by using information stored in the storage devices other than the first storage device when the first storage device fails. And information in a non-restored area in the first storage device and information in a second storage device are restored by using information stored in the storage devices other than the first and the second storage devices when the second storage device fails while the information in the first storage device is being restored.