Replacing a failed disk in DDN SFA controlled storage.

Robert Leong -

Automatic Rebuild of Swapped Drive

To configure your SFA based System to automatically rebuild a disk once the failed disk has been physically replaced you will need to ensure the pool's "Sparing Policy" is set to "SWAP".  This setting can be changed via WebUI or CLI

The setting that must be updated is the "Spare Policy"   This setting is set to AUTOMATIC by default (meaning, automatically use one of the predefined spare disks from a hot spare pool) and will need to be changed to SWAP (if a disk is added and matches the capacity of the disk that was removed, rebuild it)

The current Spare Policy can be seen either via WebUI or CLI.

ex: WebUI  (Pools > Show Storage) 


ex: CLI (show pool)

ddn RAID[0]$ show pool

*     Pool(s)     *

                                                    |Total |Free  |Max   |                   |Disk|  Global  |Spare |
Idx|Name            |State      |Chunk|Raid| Faults |cap GB|cap GB|VD GB | Settings  | Jobs  |T/O |spare pool|Policy|
 18 pool-18          NORMAL       256   6              9040      0      0  W R  IV       V     10  UNASSIGNED  SWAP  
 19 pool-19          NORMAL       256   6              9040      0      0  W R  IV       V     10  UNASSIGNED  SWAP  
 20 pool-20          NORMAL       256   6              9040      0      0  W R  IV       V     10  UNASSIGNED  SWAP  
 21 pool-21          NORMAL       256   6              9040      0      0  W R  IV       V     10  UNASSIGNED  SWAP  
 22 pool-22          NORMAL        NA   1               240     56     56  W R  IV       V     10  UNASSIGNED  SWAP  
 24 tempTest         NORMAL        NA   1               240      0      0  W R  IV       V     10  UNASSIGNED  AUTO  

Total Storage Pools: 6


To change the pools spare policy to SWAP

ex: WebUI (Pool > Set Storage Sparing Attributes)


ex: CLI (set pool=* sparing_policy=swap)

NOTE: the following command will change the sparing policy for all pools:

ddn RAID[0]$ set pool=* sparing_policy=swap
POOL 65535 OID=0xffffffff attributes set with STATUS='Success' (0x0)


NOTE: If any pools are (re)created this setting must be subsequently changed for those pools.

Manual Rebuild of Replaced Disk

Once the physical disk has been replaced, by default, the disk will need to be manually assigned to a Storage pool and assigned as a spare.

Change the state of the replacement drive to spare and assign it to a pool.

Use the SFA GUI interface: 
Physical Disks > Assign to Pool

Choose the Pool and the unassigned disk



Rebuild priority

See the 'set pool" and "show pool" for available adjustments to the rebuild priority.

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