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Obsolete Releases => SME Server 7.x => Topic started by: ddougan on May 05, 2011, 04:40:59 PM

Title: RAID Configuration Questions
Post by: ddougan on May 05, 2011, 04:40:59 PM

One of the servers I look after recently had a degraded RAID event. I confirmed the hardware status (using smartctl) and replaced the failed drive. This server is about 5 years old (an Acer tower) and as it rebooted, I went into the hardware RAID BIOS and monitored as it rebuilt the array.

After it rebooted successfully, I realized that something was odd - /proc/mdstat showed the following:

Code: [Select]

# cat /proc/mdstat
Personalities : [raid1]
md2 : active raid1 sda2[0]
      195253888 blocks [2/1] [U_]
     
md1 : active raid1 sdb1[0]
      104320 blocks [2/1] [U_]
     
unused devices: <none>


Prior to the failure, it had shown sda2 and sdb2 for md2 and sda1 and sdb1 for md1, as would be expected.

As I reviewed the RAID wiki on contribs.org, it struck me that if there is a hardware controller, the OS should have seen only one drive, not two. Am I correct in thinking this?

Has the configuration been incorrect all this time and if so, what's the best way to move forward?


Thanks for any assistance.

Title: Re: RAID Configuration Questions
Post by: Stefano on May 05, 2011, 04:57:37 PM

you are using a sw raid over a fake hw raid.. that's E V I L :-)

add your new disk via the admin console (menu 5)

for the future, don't use fake raid, let SME use sw raid

P.S.: be aware that according to your bios you are using a "HW" raid, so the data could be modified in any way by the controller.. in other words, if you change the mb/controller you could have problems to read your data

Title: Re: RAID Configuration Questions
Post by: ddougan on May 05, 2011, 05:36:44 PM

Stefano,

Thanks. I suspected that is what had happened.

Should I disable the h/w RAID, or leave it and set up via the admin console as you suggested?

Des

Title: Re: RAID Configuration Questions
Post by: Stefano on May 05, 2011, 06:19:58 PM

add the new disk via admin console.. don't change anything else

Title: Re: RAID Configuration Questions
Post by: ddougan on May 05, 2011, 06:22:01 PM

OK, thanks.

Des

Title: Re: RAID Configuration Questions
Post by: CharlieBrady on May 05, 2011, 10:22:43 PM

Quote from: Stefano on May 05, 2011, 06:19:58 PM

add the new disk via admin console.. don't change anything else

I'm not certain that that will be possible, given the current confused status of the SW RAID.

I think it should be true that /dev/sda1 is good. I would confirm that by removing /dev/sdb, and boot which /dev/sda, so that /dev/sda1 and /dev/sda2 are both active, and current. If so, then delete the partitions on the second disk, then it can be re-added via the console.

I hope that you have good backup, Des.