HP StorageWorks Scalable File Share User Manual

Page 287

Recovering degraded MDS services on systems using EVA4000 storage

9–63

In the example in the previous step, the

/dev/sdc

component is shown to have failed, while the

/dev/sdb

component is operational. You can determine which LUN the

/dev/sdc

component is

associated with by entering the command shown in the following example:

# ls -l /dev/hpls | grep sdc$
lrwxrwxrwx 1 root root 9 May 4 01:49 /dev/hpls/dev22a -> /dev/sdc

In this example, LUN 22 (

/dev/hpls/dev22a

) is the failed mirror component.

Remove the failed mirror component and then add it again, as shown in the following example:

# mdadm --remove /dev/md0 /dev/sdc
mdadm: hot removed /dev/sdc
# mdadm --add /dev/md0 /dev/sdc
mdadm: hot added /dev/sdc

NOTE:

The

mdadm --remove

command may fail. This is normal and you can proceed to run

the

mdadm --add

command.

At this point, the RAID device will recover and start to resynchronize itself. You can check the status

and progress of the resynchronization of the device using the

mdadm

command, as shown in the

following example:

# mdadm --detail /dev/md0
/dev/md0:
.

State : clean, degraded, recovering
.

Rebuild Status : 26% complete
.

Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
1 0 0 -1 removed
2 8 32 0 spare /dev/sdc

When the resynchronization is complete, the status information will change, as shown in the following

example:

# mdadm --detail /dev/md0
/dev/md0:
.

State : clean
.

Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
1 8 32 1 active sync /dev/sdc

You can check the progress of the resynchronization process by examining the event log as follows:

sfs> show log facility=storage && age < "5m"
.

2004/11/02 10:28:56 storage n south2: mds8: /proc/mdstat:
md0 : active raid1 sdc[1] sdb[0]
10485504 blocks [2/1] [U_]
[=>...................] recovery = 6.8% (721344/10485504)
finish=2.9min speed=55488K/sec
.