Areca (or other) RAID-card, what actually happens if you run into a URE during rebuid

A

ATWindsor

Weaksauce
Joined
Feb 1, 2010
Messages
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I see many articles claiming that the controller will automatically fail the rebuild if it runs into a URE (unrecoverable read error) during a rebuild, is that actually the case for areca-cards, or others? Seems like pretty stupid behavior.
 
If it's a raid5, what other choise does the raid card have?

Your rebuilding cause you lost a disk, if you have a read error on any other disk, you just lost that data, without any way to recover it, and it can't generate any parity infomation for that stripe for the rebuild.

If you just want it to like, zero out that bad section and go on, normally this is supported via an undocumented or other emergancy only repair option.
 
The card has the choice it IMHO always should use. Send an alarm when it hits an URE, continue the rebuilding, and warn about the URE in the log. For most people, 99.9% recovery is better than 0%
 
I was curious as to what happens too. I need like 14 new 4TB hard drives, and was seeing what would happen during a raid6 rebuild since URE is bound to happen. If i just lose the file data corresponding to whatever was on that URE block its no big deal to me, as long as the entire raid doesnt fail.

Else im going to have to go with a raid1+0 with more drives to get the same effective space.
 
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