I'm having problems with a USB3 HDD caddy of four disks randomly disappearing from my Ubuntu box.
As the fours disks are set up as RAID5 this is a particular nuisance, not least because I recently replaced one of the disks and it is unable to complete resyncing. I think this is a clue; it was stable until it reached ~93% complete but now every time I reassemble the array it gets to a little over 94% before it drops out again, returning to 93.7% on each reassemble. The array isn't being used (in most cases it isn't even mounted).
Looking at the logs: http://paste.ubuntu.com/5757858/
.. it starts with:
--snip-- Jun 12 09:57:14 FileServer kernel: [ 3973.912073] usb 6-2: USB disconnect, device number 2 Jun 12 09:57:14 FileServer kernel: [ 3973.912079] sd 6:0:0:2: Device offlined - not ready after error recovery Jun 12 09:57:14 FileServer kernel: [ 3973.912099] sd 6:0:0:2: [sdh] Unhandled error code Jun 12 09:57:14 FileServer kernel: [ 3973.912104] sd 6:0:0:2: [sdh] Result: hostbyte=DID_ABORT driverbyte=DRIVER_OK Jun 12 09:57:14 FileServer kernel: [ 3973.912111] sd 6:0:0:2: [sdh] CDB: Read(10): 28 40 de c4 0a 98 00 00 f0 00 --snip--
A couple of seconds later the caddy reconnects on its own, although does not reassemble the array (see link to full logs above).
Googling the error has found a number of suggestions that this is a software issue: https://bugs.launchpad.net/ubuntu/+source/hdparm/+bug/515023 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/580983
One suggestion is that this is down to /lib/udev/rules.d/85-hdparm.rule and I've made the tweak suggested to prevent it running on USB-connected drives, but I don't understand what the rule does and as such have no idea whether this is happening, or whether I have correctly disabled it for USB drives).
Suggestions?
Aside: The caddy also supports eSATA but because it needs to talk to 4 drives over one connection would need multiplier support on the eSATA card, so any suggestions for a suitable card welcomed.
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