Assign Global Hot Spare - Fujitsu ETERNUS DX60 S3 User Manual

Chapter 2 Component Management

2.1 Assign Global Hot Spare

2.1 Assign Global Hot Spare
This function registers a drive as a Global Hot Spare.
A Global Hot Spare is a spare drive (hot spare) that is registered in the RAID group instead of the failed drive
when a drive failure occurs. A Global Hot Spare, unlike a Dedicated Hot Spare, can be used by all of the RAID
groups.
If a drive fails, data copy (rebuild) to a Global Hot Spare starts automatically.
If the Copybackless function (*1) is disabled and the failed drive is replaced with a normal drive, the data is
copied back to the replacement drive. The Global Hot Spare that is used instead of the failed drive then
returns as a spare drive.
If the Copybackless function is enabled, the Hot Spare is registered in the RAID group after rebuilding and is
used as a data drive. The failed drive in the RAID group is changed to a Global Hot Spare after the rebuilding is
complete. If the failed drive is replaced with a normal drive, the replacement drive can be used as a Global Hot
Spare.
*1: "Copybackless" is a function that mounts a hot spare in the RAID group instead of the failed drive. The replaced drive
is then used as a hot spare. This function makes Copyback unnecessary.
• Drives that are currently used cannot be registered as Global Hot Spares.
• Make sure to register a Global Hot Spare with the same or a larger capacity than the data drives. If the
Global Hot Spare capacity is smaller than the data drive, the drive does not work as the hot spare.
• When a mix of Online disks, Nearline disks, SSDs, Online SEDs, Nearline SEDs, and SSD SEDs is installed
together in the ETERNUS DX, Global Hot Spare of each type is required. Register the Global Hot Spare with
the same capacity as the maximum capacity drive for each type.
• When multiple types of SSDs (SSD-M/SSD/SSD-M SED) are installed together in the ETERNUS DX, a Global
Hot Spare for each type is required. Register the Global Hot Spare with the same capacity as the maxi-
mum capacity SSD for each type.
• To use hot spares on a priority basis, make sure to register the Dedicated Hot Spare for a RAID group that
contains important data. Refer to
• If the Dedicated Hot Spare is registered for a RAID group to which a failed drive belongs, the Dedicated
Hot Spare is used before the Global Hot Spare. If there is no unused Dedicated Hot Spare and the drive
fails, the Global Hot Spare is used.
• Depending on the hot spare usage status, a drive with a different capacity and type from the failed drive
may be used.
• Hot Spares can be registered in any slots of the Controller Enclosures (CEs) (only for the ETERNUS DX60
S3/DX100 S3/DX200 S3 and the ETERNUS DX200F) and the DEs.
• To use the Copybackless function, the rebuild destination Hot Spare must satisfy some conditions. Refer
to "1.4.4 Setup Subsystem Parameters" (page 39)
"2.3 Assign Dedicated Hot Spare" (page 230)
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