In general, there are three reasons for restriping of software RAID 0 and 5 devices:
Partition Replacement: If a partition fails, you must replace it. Restriping can recover the data in a single lost partition in a RAID 5 by using parity. However, the data must be restriped from a backup tape if a partition fails in a RAID 0.
RAID Expansion: If you expand a RAID 1 or 5 device, the RAID restripes the data across all members.
RAID Stripe Size: If you increase or decrease the stripe size of a RAID 1 or 5 device, the RAID restripes the data across all members. This happens infrequently, unless you are measuring performance with different striping sizes to determine which best fits your operational needs.
If the restriping process is interrupted, the RAID recognizes that when the system reboots, and automatically continues the restriping process. You can also use iManager to pause and resume a restriping process.
When expanding a RAID 5 on Linux, if the newly added drive goes down during the restripe, the restriping continues without the new partition and puts the RAID in a degraded state with one partition missing. If the same partition comes back online, it finishes the restripe. If the partition has completely failed, after the degraded restriping is complete, you can add a new replacement partition, and the RAID restripes to fix it.
When expanding a RAID 5 on NetWare, if the newly added drive fails during the restripe, this is considered a fault and the device and its pools are automatically deactivated. If the same partition comes back online, it finishes the restripe. If the partition fails to come back online, you must re-create the RAID to the desired size and recover from backup. (Handling this type of failure with a degraded restripe recovery (same as for RAID 5 on Linux) is planned for a future release.)
To manually resume or pause the Restripe process:
In iManager, click.
For instructions, see Section 9.1.3, Accessing Roles and Tasks in iManager.
Select a server in the eDirectory tree where you are logged in.
For instructions, see Section 9.1.4, Selecting a Server to Manage.
Make sure that there is no I/O for the volumes on the RAID device by deactivating the volume.
Select the volumes in the RAID device you want to expand.
Click(NetWare) or (Linux).
Select a device in thelist.
Wait for the page to refresh before continuing.
The restriping process begins or pauses immediately. Restriping severely degrades I/O performance until the restriping is complete.