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I have an IBM blade server and we've installed RedHat Linux on the machine.

How can we check if we have both disks running as a mirror, or if everything is only running on a single disk? What linux commands can I use to discover this?

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Run lshw as root. Tell us the model/make of the storage controller your your disk is attached to. –  Zoredache Aug 4 '11 at 16:36

1 Answer 1

If you are using software RAID, you can ask for the status of the disks:

cat /proc/mdstat

You will get something like this (a mirrored pair plus a 3 disk RAID setup):

[root@myserver ~]# cat /proc/mdstat                                                                                                                                                                 Personalities : [raid1] [raid6] [raid5] [raid4]
md1 : active raid1 sde1[1] sdd1[0]
      1953511936 blocks [2/2] [UU]

md0 : active raid5 sdc1[2] sdb1[1] sda1[0]
      3907023872 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]

unused devices: <none>

If, however, you are using a hardware RAID setup based on whatever disk controller/s your blade system has fitted then you will need to check out what utilities and/or firmware-based tools are available - for the latter you may need to reboot the server and press a key combination to enter a setup program, or perhap start the server from a configuration disc.

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hi Linker I get cat /proc/mdstat Personalities : unused devices: <none> , so seems that I not have mirror and I have only one disk? –  diana Aug 4 '11 at 13:02
    
It could be that your system is using hardware RAID then, so the second half of the answer applies - your server may be sorting out the RAID configuration and presenting a single 'disk' to Linux. –  Linker3000 Aug 4 '11 at 13:05
    
Linket do you have idea if some linux command can give this info about mirror or not in place to cat the file? –  diana Aug 4 '11 at 13:12
    
Not really - but you may get a clue by looking at the system startup messages to see what disk controller/s are fitted and this may indicate whether they may have any inbuilt utilities or if you can seek out any linux-based tools. Try: dmesg | more (dmesg piped through the 'more' command) –  Linker3000 Aug 4 '11 at 13:15
    
ok so if I use dmesg | more or dmesg | grep , what I need to search? or what I need to expect? to verify mirror or not –  diana Aug 4 '11 at 13:17

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