HP StorageWorks Scalable File Share User Manual

Page 286

Troubleshooting

9–62

Identify the component LUNs that are used to mirror the LUN, using the

show lun lun_number

command as shown in the following example:

sfs> show lun 41

LUN (WWID): raid_41
.

Component LUN Size (GB)
------------- ---------
19 1900
22 1900

In this example, LUNs 19 and 22 are components of LUN 41.

As displayed by the

show filesystem

command in Step 2, the

mds8

service is running on the

south2

server. Log in to that server and determine which RAID device is associated with LUN 41, as

shown in the following example:

# ls -l /dev/hpls/dev41a

lrwxrwxrwx 1 root root 15 Nov 4 17:23 /dev/hpls/dev41a -> /dev/md0

You can confirm this by examining the

raidtab

file used to create the RAID device, as shown in the

following example:

# cat /var/raid/raidtab.mds8
DEVICE /dev/sdb
DEVICE /dev/sdc
ARRAY /dev/md0
level=raid1
num-devices=2
devices=/dev/sdb,/dev/sdc
# chunk=8 # For use by lsraidlib.tcl

Use the

mdadm

command and the

/proc/mdstat

file to examine the status of the component

device, as shown in the following example:

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

State : clean, degraded
.

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

# cat /proc/mdstat

Personalities : [linear] [raid0] [raid1] [raid5] [multipath]
read_ahead 1024 sectors
md0 : active raid1 sdc[1] (F) sdb[0]
146800576 blocks [2/1] [U_]

If you have stopped and restarted the file system or rebooted the

south2

server, the status may

indicate that the failed component is missing, instead of failed. In this case, the

mdadm

command

shows a different status, as shown in this example:

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

State : clean, degraded
.

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

Whether the component is failed or missing does not matter; proceed with the remaining steps.