where <target> is a controller. If you change the chassis name of a controller that you have set as the default target ("Setting the target" on page 62), you must reset the target.

Example commands:

=> ctrl sn=P56350D9IP903J modify ch="Lab 6" => ctrl ch="Lab 4" modify ch="Lab 6"

Managing spare drives

Assigning one or more online spare drives to an array enables you to postpone replacement of faulty drives. However, it does not increase the fault-tolerance level of any logical drives in the array. For example, a logical drive in a RAID 5 configuration suffers irretrievable data loss if two of its physical drives are simultaneously in a failed state, regardless of the number of spare drives assigned to the array.

Any drive that you want to use as a spare must meet the following criteria:

•It must be an unassigned drive or a spare for another array.

•It must be of the same type as existing drives in the array (for example, SATA or SAS).

•It must have a capacity no less than that of the smallest drive in the array.

Syntax:

<target> add spares=[#:]#:#,[#:]#:#,[#:]#:#–[#:]#:#,...allunassigned [forced]

<target> remove spares=[#:]#:#,[#:]#:#,[#:]#:#–[#:]#:#,...all

where <target> is an array (or logical drive, if the array contains only one logical drive). The forced parameter represses any warning message prompts. If you specify a drive range, any drives in the range that do not meet the previous criteria are not used.

Example commands:

=> ctrl slot=3 array B add spares=1:6

=> ctrl slot=4 array all add spares=1:5,1:7 => ctrl slot=5 array A add spares=1:1–1:5 => ctrl slot=5 array A remove spares=1:1–1:5

Setting the spare activation mode

The spare activation mode feature enables the controller firmware to activate a spare drive under the following conditions:

•When a data drive reports a predictive failure (SMART) status

•When a data drive fails; this mode is the default.

In normal operations, and for older controllers, the firmware starts rebuilding a spare drive only when a data drive fails. With the predictive failure activation mode, rebuilding can begin before the drive fails, reducing the likelihood of data loss that could occur if an additional drive fails.

Use the spareactivationmode keyword to toggle the spare activation mode for the controller between drive failure and drive predictive failure.

Syntax:

<target> modify spareactivationmode=[ failure predictive ]

Example commands:

controller slot=1 modify spareactivationmode=predictive

Operations 70