Browse Prior Art Database

Method and Means of Providing Automatic Synchronization on RAID 5 Drives

IP.com Disclosure Number: IPCOM000123846D
Original Publication Date: 1999-May-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 1 page(s) / 44K

Publishing Venue

IBM

Related People

Lee, T: AUTHOR [+3]

Abstract

This disclosure describes a function that provides a means to perform synchronization of RAID 5 logical arrays without any user intervention. This operation is performed concurrently as a background task, thus making the logical array usable at the instant of its creation. Currently, a user would have to manually synchronize a RAID 5 drive after creating it. Also, this being a foreground task, would take up a lot of time before completion and the drive becoming usable (the time for synchronization, increasing with the size of the drive). A redundant (R5) drive has to be synchronized in order to make all the data units (stripes) consistent.

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Method and Means of Providing Automatic Synchronization on RAID 5
Drives

   This disclosure describes a function that provides
a means to perform synchronization of RAID 5 logical arrays without
any user intervention.  This operation is performed concurrently as a
background task, thus making the logical array usable at the instant
of its creation. Currently, a user would have to manually synchronize
a RAID 5 drive after creating it.  Also, this being a  foreground
task, would take up a lot of time before completion and the drive
becoming usable (the time for synchronization, increasing with the
size of the drive).  A redundant (R5) drive has to be synchronized in
order to make all the data units (stripes) consistent.

   The function is implemented as explained below,
  * Any ServeRAID host application that provides a
    means of creating a RAID 5 logical drive, will send a
    CHK_CONSISTENCY command to the controller, if the logical
    drive creation was successful.
  * The controller, will route the command to the
    Check Consistency Engine in the firmware, where it is
    validated and the synchronization started if feasible or
    is registered to be started whenever feasible.  (The
    feasibility is determined by factors such as, if any
    rebuild or logical drive migration or another
    CHK_CONSISTENCY is in progress.  This happens because
    such operations are carried out per logical drive basis)
  * Synchronization...