RAID Failure

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andres101

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Anyone here know how to recover from a 2 drive failure in a RAID5 array with 3 drives?

Intel Storage Console reports all drives as fine but array as "Error State" and it refuses to rebuild the array. It says that two drives failed, but they appear ok now.
 
If you've lost 2 drives from a RAID5 array, you're dead (i.e. kiss your data bye-bye.) RAID6 would be able to recover, but not 5.
 
killadoob said:
hopefully you where not using your raid for data storage
Click to expand...

What else would I use for?

masticore said:
If you've lost 2 drives from a RAID5 array, you're dead (i.e. kiss your data bye-bye.) RAID6 would be able to recover, but not 5.
Click to expand...

Yes sure, but the Intel Storage Console reports the drives as OK. Also, why would two drives fail simultaneously? What are the chances of that happening?
 
If you know which disks are actually bad, maybe you can force the last "failed" drive online using the console.

Edit: If you're using an S5000xxx motherboard, download the latest Deployment assistant CD and use the RAID console.
 
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andres101 said:
Yes sure, but the Intel Storage Console reports the drives as OK.
Click to expand...
I had a Mylex controller do pretty much the same thing to me. It reported a drive in a 6 disc (RAID0) array as faulty. The supplier suggested we reboot the machine, and that worked ... kinda. The "faulty" disc was now no longer faulty, but the array was kaput. No matter what we tried, the controller insisted that the array was bronke. Fortunately for us the data wasn't that important (obviously not on a RAID0 array.)

andres101 said:
Also, why would two drives fail simultaneously?
Click to expand...
Murphy? Sod? Down right **** luck?

andres101 said:
What are the chances of that happening?
Click to expand...
Good enough for:
a) it to happen to you
b) the RAID standards dudes to define RAID6.
 
It happens fairly often that 2 drives fail simultaneously. If you bought a combination of ie. 1xWD + 2xSeagate or something along those lines the odds are good that the seagates will fail together if they were from the same manufacturing batch.

To combat this they brought out RAID6.

That said, if your controller sees your RAID5 array as failed in 2 places, you're pretty screwed. That could very well mean that your have a corrupt parity section split over 2 drives. Can't think of a quick fix for that...
 
masticore said:
the RAID standards dudes to define RAID6.
Click to expand...
It was not part of the original RAID specification:
A RAID 6 extends RAID 5 by adding an additional parity block, thus it uses block-level striping with two parity blocks distributed across all member disks. It was not one of the original RAID levels.
Click to expand...



masticore said:
Data != porn.
Porn > data.
Click to expand...
lol. Luckily it is only all our documentation, source code, project plans and stuff on there... nothing important :D
 
Anyone think that running Spinrite on the "broken" disks may get it to work long enough to get the data off?

I may be pi$$ing into the wind but it might be worth a shot.
 
RAID5 uses one drive for parity so you'll only be able to recover from a single drive failure. Two or more then you'll start losing data :(
 
RAID3 and RAID4 use 1 drive for parity. RAID5 (and RAID6 for that matter) splits the parity over all the drives in the array ... but I'm sure you know this.
 
masticore said:
RAID3 and RAID4 use 1 drive for parity. RAID5 (and RAID6 for that matter) splits the parity over all the drives in the array ... but I'm sure you know this.
Click to expand...

In a 3 drive RAID5 configuration the size of the array will only be the same as 2 single drives added together, hence my statement about a single drive used for parity (if I'm not mistaken) :)
 
You're not mistaken. Your wording is misleading tho. The parity is not written to only one disc, but rather across all the discs. This is true for both RAID5 and RAID6.

RAID3 (and 4) used a dedicated drive to write the parity to.
 
masticore said:
You're not mistaken. Your wording is misleading tho. The parity is not written to only one disc, but rather across all the discs. This is true for both RAID5 and RAID6.

RAID3 (and 4) used a dedicated drive to write the parity to.
Click to expand...

Indeed :) Sorry if my wording caused confusion, it made sense to me :o
 
:confused:Not that i really even know what the hell you guys are talking about:confused:
 
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