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RAID Failed Redundancy on new setup

Last response: in Storage
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November 5, 2011 6:33:52 PM

Please give this thread a quick read to get the background:

http://www.tomshardware.com/forum/ [...] w=0&nojs=0

Basically I just setup a RAID1 configuration with two 1.5TB WD drives in an external enclosure connected via eSATA to my main PC. Once they synched everything appeared to be fine and I was able to access the disk and was feeling quite proud of myself. I ran into a secondary issue however where the external enclosure kept powering off and then not waking up when the PC came out of hibernation so I've been playing with some of the power management settings trying to resolve this (specifically I set the 'Turn Off Hard Disk' option to 'Never' and the 'Link State Power Management' under PCIExpress to Off (my eSATA connection is a card on the PC)). So far this didn't fix the problem but that's another matter entirely, onto the immediate issue:

Today I was messing with some cabling behind the PC and I inadvertently knocked out the AC power plug and turned the machine off. When I rebooted my mirrored RAID array did not come up so I went into Disk Management to investigate. It showed my mirrored drives as 2 seperate entries in a 'Failed' state. It also showed a 3rd drive that it listed as 'foreign'. So after a little googling I tried reactivating the failed mirrored drive. First I gotta popup that said 'The Plex is missing' and then both drives updated with the status 'Failed Redundancy'. Some more googling and I followed this article: http://buildegg.com/bewp/?p=44 and removed the failed mirror. The drive then converted back to a simple volume that was accessible as normal with the files intact and the mirrored volume of course was removed. Next I clicked on the 'foreign' disk and selected 'Import Foreign Disk' and lo and behold it restored the 2nd disk. So now I have 2 simple volumes with the same data but no RAID1.

Anyone have any clue what the hell is going on here and how I resolve this?

thanks so much for your help
a b G Storage
November 5, 2011 7:05:17 PM

Well when you have disks in RAID and the power source to any of the disks is removed then the controller sees this as a failed drive. This will result in you receiving the failed state message you refer too. It is unusual to set up RAID in external enclosures though not impossible as you have found out. How to rebuild an array depends on your controller. There will be options when the PC boots up. You can either copy the data to a third drive and start the RAID from scratch or you can add a second blank disk to your RAID that already contains a disk with all your data on it. The controller should see the blank drive and rebuild the RAID. If I was you I would back up everything to a third drive if possible as messing with RAID can cost you all your data. Read your controllers command options very carefully before entering any options.

In fact seeing as both your disks are now merely simple volumes they are not recognised by any controller which may want to knock out the data on them when you add them to an array. If you are using Windows Software RAID (as opposed to an dedicated controller) then don't. Its not worth it. Check out a SATA Hardware add on card for PCI E. They are not expensive.
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November 5, 2011 7:46:05 PM

Wamphryi said:
Well when you have disks in RAID and the power source to any of the disks is removed then the controller sees this as a failed drive. This will result in you receiving the failed state message you refer too. It is unusual to set up RAID in external enclosures though not impossible as you have found out. How to rebuild an array depends on your controller. There will be options when the PC boots up. You can either copy the data to a third drive and start the RAID from scratch or you can add a second blank disk to your RAID that already contains a disk with all your data on it. The controller should see the blank drive and rebuild the RAID. If I was you I would back up everything to a third drive if possible as messing with RAID can cost you all your data. Read your controllers command options very carefully before entering any options.

In fact seeing as both your disks are now merely simple volumes they are not recognised by any controller which may want to knock out the data on them when you add them to an array. If you are using Windows Software RAID (as opposed to an dedicated controller) then don't. Its not worth it. Check out a SATA Hardware add on card for PCI E. They are not expensive.


That doesn't make any sense, if all it took to bring down a RAID array was a simple power outage then no one would ever use them. For example my main PC also has two onboard drives that are configured in RAID1 and that machine has gone thru dozens of power outages without it destroying the array.

To clarify, I have 2 issues here, the first is that that when the main PC goes to sleep at night, the external enclosure powers down as well (which is fine if it wakes up again when the PC awakes, but so far I haven't been able to get that to work). That issue is unrelated to this RAID failure as it has happened several times and the array was fine (I just had to re-power on the enclosure and everything came back up ok). I only mentioned this because I had changed a couple settings trying to get that working. The second issue was me stupidly knocking out the PCs power cable and after reboot the RAID array was hosed, that's what I guess I'm not understanding, how that could even happen

I'm using Windows RAID for this because I had read that it works and performs fine. Should I not do that and instead use the RAID utility that is installed on the PC (it comes up during the boot sequence with the BIOS). I'm sorry if I'm being obtuse here, I just have never done this before and while I don't mind rebuilding it all from scratch I do want to make sure I do it right this time ;) 

thanks
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November 7, 2011 3:08:25 AM

no ideas gang? I guess I'll just rebuild it (from scratch this time) and see if that works better...I just expected that this wouldn't be so flawed
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!