Web Hosting Talk : Web Hosting Main Forums : Dedicated Server : Hardware experts: Is it harder to recover from RAID1 or RAID5 crashes?

[universal2001]

Calling all hardware experts or staff members who deal with a lot of hardware issues (NOC staff, etc).

I've heard a lot of instances whereby its not possible to recover a RAID-1 / RAID-5 array. Do you know which type of array is generally easier to recover and which array usually fails and is much harder to recover??

Also, please mention your preferred raid setup, raid1 or raid5.

[polarbear]

Correct me if I'm wrong, but isn't RAID-1 just one drive mirroring the other? If so, RAID-1 shouldn't cause much trouble with recovery. In fact, it should make data recovery a non-issue, as if one drive goes down, you just swap to the other.

Came over this site by goggling for "raid": http://www.acnc.com/raid.html

Explains in short terms what the differences are.

[universal2001]

Yes RAID-1 is just mirroring but I've had a few instances whereby the NOC was UNABLE to recover from a RAID1 array. It sounds funny but it has happened, thus why I asked.

[GrindKore]

Is it possible? Yes in raid 1 both HDs can go bad due to power surge or overheating. Under normal conditions I have never had both go bad on me at the same time.

[porcupine]

Depends on the controller. Typically only the higher end controllers will do RAID 5, thus in a sense, RAID 5 might be easier to recover from (as theres no shortage of pathetic RAID cards that are great, until the array degrades).

On that note though, from a technical standpoint, RAID 1 should be easier to recover from (in most casesm you shouldn't even need to recover, you should be able to pull the working drive directly from the controller and drop it into the system), though with bad RAID cards, thats not always the case.

I can recall a highpoint controller that a customer had doing raid 0+1, he lost one drive and the array was permanently stuck in degraded mode. Countless hours were spent after inserting a new drive trying to rebuild to no avail, firmware upgrades, etc. Needless to say, he replaced it with a 3ware card (much nicer) and we 'fed' the old one to the elevator (The elevators have no 'touch' sensors in 151, and will crush most small objects with glee).

[Coolraul]

My experience is that if that happens where both elements of a raid 1 array goes bad, then they are likely not bad probably its the controller.

I have only had one occasion where by replacing the controller in that case it wasn't recoverable but that was my first occurance with it and I think it was because I tried some funny stuff to recover. Mind you that was like 1992 some old mylex controller blah. I have had it happen since a couple of times and in I just switched the raid card.