Browse Prior Art Database

Concurrent drive firmware uploads in RAID storage arrays

IP.com Disclosure Number: IPCOM000129850D
Original Publication Date: 2005-Oct-07
Included in the Prior Art Database: 2005-Oct-07
Document File: 3 page(s) / 73K

Publishing Venue

IBM

Abstract

This disclosure describes a robust process to allow a concurrent upgrade of disk drive firmware in a RAID array. The process allows for uninterrupted access to the storage array and ensures that the array remains in an optimal condition. A hot-spare is used as a stand-in for the drive to be upgraded, thereby allowing a disruptive drive-level firmware upgrade to occur without any impact on the storage array as a whole. In addition, the mirrored hot-spare is only removed from the configuration when there is sufficient confidence in the new firmware image; allowing a seamless failover from the upgraded drive it its behaviour is considered unacceptable. The disclosed approach offers improved protection from the effects of a corrupt or otherwise defective firmware image.

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Concurrent drive firmware uploads in RAID storage arrays

Disclosed is a robust approach to provide uninterrupted access to data on a RAID storage array during a disruptive drive firmware upgrade process. The process described is capable of keeping the RAID array in an optimal condition throughout the upgrade process, even when the individual drive code load process is itself a disruptive operation. This approach also offers improved protection from the effects of a corrupt or otherwise defective firmware image.

    The current procedures to upgrade drive firmware in storage arrays are often disruptive, requiring all access to the disks to be quiesced for the duration of the code load. This approach imposes downtime on the host applications which require access to the data on the storage array. Where concurrent procedures do exist, then they may cause the storage array to enter a degraded state (where the subsequent failure of a disk whilst in this state will result in data loss). Current strategies also offer little protection from a defective firmware image.

    This invention makes use of the existing 'hot-spare' concept in RAID arrays, to maintain an optimal array condition throughout the upgrade procedure. Using a hot-spare as a mirror of the drive to be upgraded allows a disruptive drive-level firmware upgrade to occur, without any impact on the storage array as a whole. In addition, the mirrored hot-spare is only removed from the configuration when there is sufficient confidence in the new firmware image; allowing a seamless failover from the upgraded drive if its behaviour is considered unacceptable. This mechanism provides enhanced protection from a corrupt or defective firmware image.

    With an array containing disks Dn, with hot-spare (HS), an overview of the process is shown by the flowchart below:

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Hot spare (HS) brought up as a mirror of D0

Once the data on HS is synchronised with D0 then the RAID array can be re-associated with HS taking the place of D0, removing D0 from the config...