Hello, a friend of mine had a RAID5 set up in his PC, with 4 identical hard disks (4x WD1500 ADFD-0 150GB) on a ICH9R controller (built-in on his motherboard). This RAID5 is the only storage of this PC and is also the windows partition (huge error, I know). Now one of the hard disk seems to have gone bad and the PC cannot load windows, giving error message "DISK BOOT FAILURE INSERT SYSTEM DISK AND PRESS ENTER" When I enter the POST Matrix Storage Manager (ctrl+i during POST) it shows 3 hard discs as RAID MEMBER, and one of the hard disks as "OFFLINE MEMBER. The Raid status is FAILED. I'd guess that what I should do now is rebuild or recover the array, but the only options on the screen are: 1: Create RAID Volume 2: Delete RAID Volume 3: Reset disks to non-RAID 4: Exit Tried googling but almost every solution I found was using the windows Matrix Storage Manager program (i cannot log in windows) or mentioned an option/dialog in the POST Storage Manager saying "Rebuild Array?" (which is not the case for me). From what I know RAID5 allows for 1 hard disk to fail without loosing your data. So 1 hard disk failed! What should we do know?! We can afford loosing the data so this is not a "OMG NO BACKUP WHAT SHOULD I DO" post, but it would be nice if I didn't loose them. Every help is welcome. PS: Another peculiar thing is that from what I've read, with only 1 failed HD the raid status should be "degraded", with 2 failed HDs it should be "failed". But I have 1 failed HD (offline member) and a status of "Failed".
Did the computer have a system failure just before the first disk gave way? The reason I ask is that if a crash happened while there were active writes, the parity of the stripe may have become desynched from the data. If that happens and then a disk or block fails, you can kiss goodbye to the data across the drives. This is fixed in a business environment with a battery-backed cache, but most homes don't tend to use that.
Are you sure it's RAID 5. RAID 5 should degrade if 1 disc fails not fail. It sounds like more than 1 drive has failed even though it's not being listed as totally failed. First of all check all the sata cables & power to check if the drive is actually dead. Then try booting off a live libnux CD and see fi you can see the array
Owner of the PC does not remember a system failure prior to this. Just the PC refused to boot into windows one day.
Yes I am sure. Owner of the PC remembers setting a RAID5, and it's what I see on the screen of the Matrix Storage Manager (RAID5). Checked all the cables (data and power), even switched some data cables around to double check. Still, one of the Hard disks (the same one) pops up as OFFLINE MEMBER. Tried booting from an Ubuntu live CD. Could not access the data in the drives. But I am not good at linux. Is there a special program / command I can use to rebuild / check the Raid status?
The fact it's coming up asking for a system disk would make me suspect that some sort of corruption or crash has caused the parity to desynch. It's one of the main reasons I never recommend more than Raid 1/0/10 for home use.
so, I should kiss the raid5 goodbye? It really strikes me as odd since Raid5 was made for exactly this scenario (1 hd fails) but I cannot seem to do anything about it?!
RAID 5 WAS made for that scenario, but the write-hole bug (which is fixed by using a battery-backed cache) is why anything other than businesses don't usually use it Try replacing the drive and see if it rebuilds the parity. If not, then I'm afraid it sounds like the parity has become corrupted. If your friend wants a more home-friendly version, might I suggest RAID 10.
No.. just stop putting your boot partition on it. Just because Windows can't boot from it doesn't mean it's not working in degraded mode. The problem is that a drive failed while windows was writing something essential and the parity data is messed ... so the file concerned is corrupt. This can happen on a single disk system as much as RAID5. Just get another single hard disk, and have that as your your boot partition. Get into windows, and rebuild the RAID once you have replaced the disk.
I tried connecting a new hard disc (larger than the other 3, as I cannot find a same one) as a replacement, is shows up as "non RAID disc"in POST storage manager, still no option to rebuild/recover.
I agree 100%, raid5 as main OS disc is not wise. I'm trying this as we speak. I also took images (through a live ubuntu cd) of the 3 healthy discs, just in case.
If the worst comes to the worst you can use this to try and rebuild the data http://www.runtime.org/raid.htm
