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RAID 5: 1 drive is rebuilding and 1 not in the array

I came in this morning and my server is down.  Boot it up and I get a hard drive failure.  So I go into the adaptec manager and Drive 1 is up, Drive 2 is rebuilding, Drive 3 isnt anything - its just greyed out, but it used to be part of the array, and drive 4 is a Hot Spare. The RAID 5 array has a yellow exclmation point and a status of critical.   Once this rebuild finishes will this server come back up?  If not is there anything I can do to recover this server.  

The controller posts RAID 5 failed.  I went into the configuration (ctl-A) and verified drives 2 and 3 and they both finished successfully.  If I do wait on the rebuild - how long can I expect to wait? If the rebuild doesnt work is there ANYTHING I can do?
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I would be patient, if 2 of the drives come back online you will be able to start the server and implement the hot spare.
It could take several hours for the rebuild to complete depending on size of the disks and speed of drives.

Author

Commented:
Thanks!  We had one server get killed yesterday (lost its mirror so that was easy enough to recover) and we got it p2v'd after that.  If I can get this one - its p2v time again.  We are having power issues bad right now - ugh
Yes, it takes a long time to rebuild a drive because of the data has to be calculated.  

As you may know, a RAID5 can have 3 or 4 drives.  3 drives means that there is no hot spare.  In that case, if 1 drive fails, your data is still available however performance is very slow since the data that was on the missing drive has to be calculated.  If 2 drives fail - your data is now damaged and has to be recovered from an external backup.  

In your case you had 4 drives, the 4th one being the hot spare.  In that case RAID5 will automatically rebuild the failed drive but it takes quite a while to recreate the data.  Once that is done, the RAID5 will return to full performance (except of course you no longer have a hot spare).    With a functioning hot spare you have better protection: if 1 drive fails, the RAID performance will return to normal once the drive is rebuilt.  If 2 drives fail (not at the same time), you still have your data albeit at a reduced performance. If 3 drives fail, your data is now damaged and has to be recovered from an external backup.  

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Commented:
If it is really rebuilding wouldnt the hard drive light be working hard?  It is doing nothing at all.  Maybe I am not good at being patient
How long has it been rebuilding?

Author

Commented:
Just a couple of hours.  If it is rebooted do you know if the rebuilding start where it leaves off or starts over?  I have been working on it trying different things all day so I have interrupted it several times.  However I am leaving it alone at least until the morning.  I just find it odd that it is rebuilding and not showing hd activity.  
It is odd that it is not showing HDD activity.  Most controllers will continue where they left off after a reboot. What type of controller is it?

Author

Commented:
Adaptec 2410. Its a SATA RAID card.
Unfortunatley I would wait, although I am not sure about the fact that it is rebuilding.  Here is an omnious statement from Adaptec:

If a single drive fails and the RAID 5 array is marked degraded, yes, the data on the array should still be available. The data should remain available when the failed drive is replaced and during the rebuild procedure. The access speed of the data in the array may decrease during the time the array is degraded or rebuilding to the replacement drive. Once the rebuild is complete the normal speed will resume.
 
If more than one drive has failed the data will not be accessible. Only one drive in a RAID 5 array can fail and still be accessible. If a multiple drive failure in a RAID 5 is experienced, please contact Adaptec Technical Support for possible recovery options.

Author

Commented:
Im hear you.  I dont think its rebuilding, but I am willing to go to sleep and find out in the morning.  No HD activity is the kicker to me.  
Is this your device?

http://www.adaptec.com/en-us/support/raid/sata/aar-2410sa/index.htm

Here is a user's guide that says on page 28 that the hrconf setstate command can be used to rebuild the drive (RBL).

http://download.adaptec.com/pdfs/user_guides/command_line_interface_for_internal_raid_users_guide_09_06.pdf

Author

Commented:
So - This morning I come in and drive 2 still is rebuilding.  I reboot a couple of times trying different things and now it shows drive 1 and 2 as online.  Drive 3 is still greyed out for what ever reason even though it sees it in the configuration.  And the hotspare is online.  However.. the RAID5 now says offline with the red x on it.  I dont see anywhere to make it come back online.  
Can you run either HRCONF or ARCONF at the command line?
Dr. KlahnPrincipal Software Engineer
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