Weird thing with gmirror
Damian Wiest
dwiest at vailsys.com
Tue Oct 3 12:59:34 PDT 2006
On Tue, Oct 03, 2006 at 06:22:16PM +0200, Jeremie Le Hen wrote:
> Hi,
>
> (Please Cc: me in your replies, I am not subscribed.)
>
> I am using:
> % obiwan:tataz$ uname -mv
> % FreeBSD 6.1-STABLE #8: Sun Jun 25 18:27:14 CEST 2006 root at obiwan:/usr/obj/usr/src/sys/OBIWAN i386
>
> I have set up a mirror gm1 using gmirror(8), with ad1 and ad2 as providers.
> This had worked pretty well for weeks, until I got the following error:
>
> % ad1: FAILURE - READ_DMA status=51<READY,DSC,ERROR> error=40<UNCORRECTABLE> LBA=6170832
> % GEOM_MIRROR: Request failed (error=5). ad1[READ(offset=3159465984, length=65536)]
> % GEOM_MIRROR: Device gm1: provider ad1 disconnected.
One of the drives had a read error and was removed from the mirror.
> Obviously, my hard drive (Maxtor's drives really, really suck) is going
> sick. But as usual, a mere reboot seems to improves the disk state, for
> a while at least.
There's no need to reboot.
> I have rebooted the box, but now the kernel says:
>
> % GEOM_MIRROR: Device gm1 created (id=1340871616).
> % GEOM_MIRROR: Device gm1: provider ad1 detected.
> % GEOM_MIRROR: Device gm1: provider ad2 detected.
> % GEOM_MIRROR: Component ad1 (device gm1) broken, skipping.
>
> And gmirror(8)'s output is:
>
> % Geom name: gm1
> % State: DEGRADED
> % Components: 2
> % Balance: split
> % Slice: 4096
> % Flags: NONE
> % GenID: 1
> % SyncID: 1
> % ID: 1340871616
> % Providers:
> % 1. Name: mirror/gm1
> % Mediasize: 81964301824 (76G)
> % Sectorsize: 512
> % Mode: r1w1e2
> % Consumers:
> % 1. Name: ad2
> % Mediasize: 81964302336 (76G)
> % Sectorsize: 512
> % Mode: r1w1e1
> % State: ACTIVE
> % Priority: 0
> % Flags: NONE
> % GenID: 1
> % SyncID: 1
> % ID: 1733588705
>
> What am I suppose to do from here ?
>
> I've performed the following commands:
>
> % obiwan:root# gmirror forget gm1 ad1
> % obiwan:root# gmirror insert gm1 ad1
>
> But the whole disk is then wholly resynchronized. Is there any faster
> way to reconnecte ad1 to gm1 ?
>
> Thank you !
> --
> Jeremie Le Hen
> < jeremie at le-hen dot org >< ttz at chchile dot org >
> _______________________________________________
I believe you could have omitted the "gmirror forget".
AFAIK, the disks must be resynchronized since it's possible that changes
were made since the sub-mirror was detached. Using a filesystem that
does logging would allow the possibility of skipping a resync of the
entire disk, but I don't believe geom supports this.
-Damian
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