Software RAID doubt

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Operating Systems Linux Red Hat Software RAID doubt
# 1  
Old 07-31-2009
Software RAID doubt

hi friends,
I am having issues with adding a spare device to a failed array.

I have created RAID 1 with 3 partitions using mdadm command. Later I added a spare with
mdadm --add /dev/md0 /dev/sdb6

This works fine and when I check this with mdadm --detail command it just sits there as a spare device.
And now, if I set one of the active raid device in the array as faulty, the spare device becomes active and the failed device becomes faulty spare. This looks perfect, but once i reboot the machine and type mdadm --detail /dev/md0, both the failed device as well as the spare device are not seen in the array..

Why is this happening...where am i going wrong..?

pls help
# 2  
Old 07-31-2009
what does your mdadm.conf file look like?

what about /proc/mdstat?
# 3  
Old 07-31-2009
hi mark, i dont have an mdadm.conf file...(This is RHEL 5 system). I could not locate where this file is...sorry.
# 4  
Old 08-01-2009
What is the ouput from mdadm --detail?

You should have an /etc/mdadm.conf configuration file. If you do not have one, you need to create one.
# 5  
Old 08-02-2009
Initial stage of the raid array:
mdadm --detail /dev/md0

    Number   Major   Minor   RaidDevice State
       0       3       11        0      active sync   /dev/hda11
       1       3       12        1      active sync   /dev/hda12
       2       3       13        2      active sync   /dev/hda13

       3      3        14       -       spare   /dev/hda14

after the mdadm --fail /dev/hda13
    Number   Major   Minor   RaidDevice State
       0       3       11        0      active sync   /dev/hda11
       1       3       12        1      active sync   /dev/hda12
       2       3       14       2      active sync   /dev/hda14

      3      3        13      -       faulty spare     /dev/hda13

after rebooting..
both the faulty spare (/dev/hda13) and the newly active raid device (/dev/hda14) are removed from the array... and only /dev/hda11 and /dev/hda12 are active.
I touched a file named /etc/mdadm.conf, but nothing is configured there nor any output from that file..
# 6  
Old 08-03-2009
do this:

mdadm --examine --scan > /etc/mdadm.conf

---------- Post updated at 12:58 AM ---------- Previous update was at 12:56 AM ----------

I touched a file named /etc/mdadm.conf, but nothing is configured there nor any output from that file..[/QUOTE]

It is a conf file, not a log, so you won't get output. This is probably why you are having your issues. I have given the command on how to create this file.
# 7  
Old 08-04-2009
hi mark,
thanks. I will do as u guided and let u know the results.bye.

---------- Post updated 08-04-09 at 10:19 PM ---------- Previous update was 08-03-09 at 11:08 PM ----------

mark, I have tried as you mentioned, but i am not successful. The same things happen after I set one of the active device as faulty, (both the faulty device as well as the spare device gets removed...).
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