gconcat incorrect superblock after adding a disk

[Eric Anderson]

On 07/14/07 20:47, Aaron Hurt wrote:
> I have a fairly decent sized gconcat array composed of 4 disks (ad8 ad10
> ad12 ad14) the previous working members.  Recently I tried to add
> another disk using the following procedure:
> 
> umount /dev/concat/store1
> gconcat stop store1
> gconcat label store1 ad8 ad10 ad12 ad14 ad4
> growfs /dev/concat/store1
> 
> ..... it was at this point that I got the incorrect superblock error
> after adding ad4.  Now, even if I try to remove ad4 and label with the
> original disks (keeping the original order) it still will not mount or
> fsck.  The exact messages are below:
> 
> schroder# mount /dev/concat/store1 /store
> mount: /dev/concat/store1 on /store: incorrect super block
> 
> Geom name: store1
> State: UP
> Status: Total=4, Online=4
> Type: AUTOMATIC
> ID: 1480896172
> Providers:
> 1. Name: concat/store1
>   Mediasize: 640167540736 (596G)
>   Sectorsize: 512
>   Mode: r0w0e0
> Consumers:
> 1. Name: ad8
>   Mediasize: 120034123776 (112G)
>   Sectorsize: 512
>   Mode: r0w0e0
>   Start: 0
>   End: 120034123264
> 2. Name: ad10
>   Mediasize: 200049647616 (186G)
>   Sectorsize: 512
>   Mode: r0w0e0
>   Start: 120034123264
>   End: 320083770368
> 3. Name: ad12
>   Mediasize: 160041885696 (149G)
>   Sectorsize: 512
>   Mode: r0w0e0
>   Start: 320083770368
>   End: 480125655552
> 4. Name: ad14
>   Mediasize: 160041885696 (149G)
>   Sectorsize: 512
>   Mode: r0w0e0
>   Start: 480125655552
>   End: 640167540736
> 
> schroder# fdisk /dev/concat/store1
> ******* Working on device /dev/concat/store1 *******
> parameters extracted from in-core disklabel are:
> cylinders=77829 heads=255 sectors/track=63 (16065 blks/cyl)
> 
> Figures below won't work with BIOS for partitions not in cyl 1
> parameters to be used for BIOS calculations are:
> cylinders=77829 heads=255 sectors/track=63 (16065 blks/cyl)
> 
> fdisk: invalid fdisk partition table found
> Media sector size is 512
> Warning: BIOS sector numbering starts with sector 1
> Information from DOS bootblock is:
> The data for partition 1 is:
> sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
>    start 63, size 1250322822 (610509 Meg), flag 80 (active)
>        beg: cyl 0/ head 1/ sector 1;
>        end: cyl 4/ head 254/ sector 63
> The data for partition 2 is:
> <UNUSED>
> The data for partition 3 is:
> <UNUSED>
> The data for partition 4 is:
> <UNUSED>
> 
> 
> 
> Any and all help or suggestions would be appreciated.  I can be reached
> via this email address or by my cell phone number below.  The data is
> not life threatening since it is just my home server, but there are
> several hundred gigs of personal movie clips, family photos and music
> and whatnot.  I would really like to be able to save this data if at all
> possible (and then make an immediate backup of it).  I do believe I will
> be purchasing some more disks soon for a seperate duplicate machine that
> can clone this storage box.


First, once you add a disk to a concat, and grow the file system, I 
would not recommend removing the disk from the concat.  If possible, and 
you haven't written anything else to it, put it back on the concat, and 
then move forward.

It looks like you have a slice on that concat, but you are trying to 
mount the device, not the slice.  Did you first fsck the partition after 
you did a growfs, and before attempting a mount?

I would suspect (if you can get the disk back in the concat, and you 
have not already written over it) that you can just do something like:

fsck -y /dev/concat/store1s1
or
fsck -y /dev/concat/store1s1a maybe

and then mount it using that name.  Do a:

ls -al /dev/concat/store1*

and send that output.

Also, for what it's worth, when you add drives to make a single device 
without any redundancy, you increase your chances of a total failure. 
The more drives, the less resilient.

Eric