OWC Qx2 constantly rebuilds

MikeyWard

macrumors newbie
Original poster
Jun 30, 2019
2
0
Hey y’all,

I have a OWC Mercury Elite-AL Pro Qx2 that I’ve been using for my iTunes library. It’s configured RAID5, 4x2TB. About 2/3 full.

Last time I turned it on, it started rebuilding out of the blue. No indication of drive failures.

It’s been running/rebuilding for about 6.5 days now. How boned am I? What should my next steps be?

 

Stephen.R

macrumors 65816
Nov 2, 2018
1,363
904
Thailand
Raid5 is notorious for one drive failing, and then the increased load of rebuilding onto a spare/replacement kills another drive.

How big are the drives (or the total usable space if that’s easier)? Do you have a backup of the iTunes library?
 

MikeyWard

macrumors newbie
Original poster
Jun 30, 2019
2
0
Currently configured with 4 2tb drives. About 2/3 full. No backup, but most of it is redownloadable purchases. Would need to re-rip about 120 CD, as I never got iTunes Match, so it’s not a total loss if the array is hosed, just a big pain in the rear.
[doublepost=1561919291][/doublepost]Not worth paying for data recovery (~$1200 or so, yeah?) but might consider replacing the enclosure if you thinks that’s the problem. But it sounds like you suspect multiple disk failure?

Big question mark for me is, shouldn’t the enclosure’s disk LED indicate at least one as failing, instead of endlessly trying to rebuild?
 

Stephen.R

macrumors 65816
Nov 2, 2018
1,363
904
Thailand
If you had multiple disk failures it wouldn’t mount, what’s weird is that it tells you (somehow? Via software?) that it’s rebuilding but you haven’t replaced a disk? So what exactly is it rebuilding? Maybe it detected an error in the parity disk and is rebuilding it?

My comment about raid5 causing cascade failures was more of a warning to not use raid5 than a theory on the current behaviour.

Are there any specific logs or information it provides you about the rebuild (In particular what and why it’s rebuilding) ?




I like you once had iTunes stuff on a raid5 device (actually two successive ones, both from LaCie).

I gave up after two. They’re expensive and usually cause more hassle than they solve when a drive fails. I’m currently using a software raid 1+0 (a raid 0 set over two raid 1 sets) over 4x3tb disks. It works well except for occasional misleading error messages in the Disk Utility GUI (the terminal diskutil command shows correct statuses though). If I up the game to 8 or 10 tb disks I can probably get away with regular raid1.
 

hfg

macrumors 68040
Dec 1, 2006
3,566
276
Cedar Rapids, IA. USA
What kind of disks are you using in the Qx2? Since it is hardware RAID, it is really sensitive to the startup speed of the disks to "ready state", and thus doesn't work well with many "green" low power disks. If one disk indicates "not ready", I think it votes it out of the array ... but then sees it as "replaced" once up to speed and rebuilds the array.