When running a RAID 3 or 5 (if you configured one or more drives to be spares) the 5070 will detect when a drive goes offline and automatically select a spare from the spares pool to replace it. The data will be rebuilt on-the-fly. The RAID will continue operating normally during the re-construction process (i.e. it can be read from and written to just is if nothing has happened). When a backend fails you will see messages similar to the following displayed on the 5070 console:
930 secs: Redo:1:1 Retry:1 (DIO_cim_homes_D1.1.0_q1) CDB=28(Read_10)Re-/Selection Time-out @682400+16
932 secs: Redo:1:1 Retry:2 (DIO_cim_homes_D1.1.0_q1) CDB=28(Read_10)Re-/Selection Time-out @682400+16
933 secs: Redo:1:1 Retry:3 (DIO_cim_homes_D1.1.0_q1) CDB=28(Read_10)Re-/Selection Time-out @682400+16
934 secs: CIO_cim_homes_q3 R5_W(3412000, 16): Pre-Read drive 4 (D1.1.0) fails with result "Re-/Selection Time-out"
934 secs: CIO_cim_homes_q2 R5: Drained alternate jobs for drive 4 (D1.1.0)
934 secs: CIO_cim_homes_q2 R5: Drained alternate jobs for drive 4 (D1.1.0) RPT 1/0
934 secs: CIO_cim_homes_q2 R5_W(524288, 16): Initial Pre-Read drive 4 (D1.1.0) fails with result "Re-/Selection Time-out"
935 secs: Redo:1:0 Retry:1 (DIO_cim_homes_D1.0.0_q1) CDB=28(Read_10)SCSI Bus ~Reset detected @210544+16
936 secs: Failed:1:1 Retry:0 (rconf) CDB=2A(Write_10)Re-/Selection Time-out @4194866+128
Then you will see the spare being pulled from the spares pool, spun up, tested, engaged, and the data reconstructed.
937 secs: autorepair pid=1149 /raid/cim_homes: Spinning up spare device
938 secs: autorepair pid=1149 /raid/cim_homes: Testing spare device/dev/hd/1.5.0/data
939 secs: autorepair pid=1149 /raid/cim_homes: engaging hot spare ...
939 secs: autorepair pid=1149 /raid/cim_homes: reconstructing drive 4 ...
939 secs: 1054
939 secs: Rebuild on /raid/cim_homes/repair: Max buffer 2800 in 7491 reads, priority 6 sleep 500
The rebuild script will printout its progress every 10% of the job completed
939 secs: Rebuild on /raid/cim_homes/repair @ 0/7491
1920 secs: Rebuild on /raid/cim_homes/repair @ 1498/7491
2414 secs: Rebuild on /raid/cim_homes/repair @ 2247/7491
2906 secs: Rebuild on /raid/cim_homes/repair @ 2996/7491
After you have replaced the bad drive you must re-integrate it into the RAID set using the following procedure.
replace <name> <backend>
Where <name> is whatever you named the raid set and <backend> is the ID of the backend that is being re-integrated into the RAID. If a spare was in use it will be automatically returned to the spares pool. Be patient, reconstruction can take a few minutes to several hours depending on the RAID level and the size. Fortunately, you can use the RAID as you normally would during this process.