Re: power interruption -> renamed USB disk
On Mon, 2011-03-07 at 18:02 -0600, Ron Johnson wrote:
> On 03/07/2011 03:08 PM, Ross Boylan wrote:
> > I have a SATA disk in an external USB docking station. The computer it
> > is attached to is on UPS, but the external disk has only surge
> > protection.
> >
> > When the power goes out for a moment, the disk, which was /dev/sdc,
> > seems to come back as /dev/sdd. The disk has a partition that is part
> > of an LVM volume group, and the file system on the disk is inaccessible.
> >
> > I've had to restart the system to get the disk back.
> >
> > Is there a better way (aside from getting the disk on UPS)?
> >
> > Debian Lenny (mostly), 2.6.26-2-686 stock Debian kernel on Pentium 4
> > chip w/hyperthreading. The disk uses the GPT partition format.
> >
> > Most recent incident:
> > <log>
> > #power fails
> > Mar 7 11:21:18 corn kernel: [182529.931888] ethfast: Link is Down
> > Mar 7 11:21:18 corn kernel: [182530.140155] usb 5-3: USB disconnect, address 4
> > Mar 7 11:21:18 corn kernel: [182530.140155] usb 5-3.1: USB disconnect, address 7
> > Mar 7 11:21:18 corn kernel: [182530.140155] usb 5-3.2: USB disconnect, address 8
> > Mar 7 11:21:18 corn kernel: [182530.140155] usblp0: removed
> > Mar 7 11:21:18 corn kernel: [182530.375701] usb 5-4: USB disconnect, address 5
> > #power resumes
> > Mar 7 11:21:21 corn kernel: [182533.121591] usb 5-3: new high speed USB device using ehci_hcd and address 9
> > Mar 7 11:21:21 corn kernel: [182533.179788] hub 5-0:1.0: unable to enumerate USB device on port 3
> > Mar 7 11:21:30 corn kernel: [182542.755370] __ratelimit: 4 messages suppressed
> > Mar 7 11:21:30 corn kernel: [182542.755379] Buffer I/O error on device dm-15, logical block 8210
> > Mar 7 11:21:30 corn kernel: [182542.755384] lost page write due to I/O error on dm-15
> [snip]
> > Mar 7 11:43:33 corn kernel: [183938.589854] nfsd: last server has exited
> > Mar 7 11:43:33 corn kernel: [183938.614722] nfsd: unexporting all filesystems
> > </log>
> >
>
> Why are you using device names instead of labels or UUIDs?
/dev/sdc (or sdd on power resume) is what the kernel is handing me; is
there a way to change that?
My understanding is that LVM uses UUID's, which makes its failure to
recover a bit more puzzling to me.
I suspect I'm not fully understanding the question.
Ross
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