Upgrading The Disk Firmware Non-Disruptively - IBM N Series Hardware Manual

The underlying feature that enables disk firmware NDU, called
provided by the option raid.background_disk_fw_update.enable. This option is set to On
(enabled) by default.
Momentary disk offline is also used as a resiliency feature as part of the error recovery
process for abnormally slow or nonresponsive disk drives. Services and data continue to be
available throughout the disk firmware upgrade process.
Beginning with Data ONTAP 8.0.2, all drives that are members of RAID-DP or RAID 4
aggregates are upgraded nondisruptively in the background. Still, upgrade all disk firmware
before doing a Data ONTAP NDU.

20.3.2 Upgrading the disk firmware non-disruptively

Nondisruptive upgrades are performed by downloading the most recent firmware from the
IBM Support site to the controller's /etc/disk_fw directory. Updates start automatically for
any disk drives that are eligible for an update. Data ONTAP polls approximately once per
minute to detect new firmware in the /etc/disk_fw directory. Firmware must be downloaded
to each node in an HA pair configuration. During an automatic download, the firmware is not
downloaded to an HA pair partner's disks.
Automatic disk firmware upgrade
Background disk firmware updates do not occur if either of the following conditions is
encountered:
Degraded volumes exist on the storage system
Disk drives that need a firmware update are present in a volume or plex that is in an offline
state
Updates start or resume when these conditions are resolved.
Make sure that the process occurs automatically. Do not manually use the disk_fw_update
command. Set systems with large numbers of disks to upgrade automatically overnight. If the
option raid.background_disk_fw_update.enable is set to On (enabled), disk firmware
upgrade occurs automatically only to disks that can be offlined successfully from active file
system RAID groups and from the spare pool.
Firmware updates for disks in RAID 4 volumes are performed disruptively upon controller
boot unless the disk firmware is removed from the /etc/disk_fw directory beforehand.
RAID 4 volumes can be temporarily (or permanently) upgraded to RAID-DP to automatically
enable background firmware updates (excluding gateway models). This operation doubles the
RAID group size. It therefore requires sufficient spares to add one double-parity disk drive for
each RAID group in a volume. To convert a traditional volume from RAID 4 to RAID-DP,
perform these steps:
1. Convert the volume to RAID-DP by running the vol options <volume> raidtype raid_dp
command. Wait for double-parity reconstruction to complete.
2. Perform the automatic background disk firmware NDU as usual, followed by the Data
ONTAP NDU if necessary.
3. If wanted, convert the volume back to RAID 4 by using the vol options <volume>
raidtype raid4 command. This operation takes effect immediately. As a result, the
double-parity drive is ejected from the RAID groups, and the RAID group size is halved.
momentary disk offline
Chapter 20. Designing for nondisruptive upgrades
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