7Tb XFS partition lost on reboot

Hi !
(I'm on Ubuntu 7.10 64 bits)
I have array of 12 750gb disks in hardware Raid 6 that gives me a 7Tb partition. I tried to format it in ext3, but it took too much time, so I tried in Reiserfs, but the partition were lost on reboot, and now i'm trying XFS.

So I created the partition with parted, because fdisk can't do more that 2tb partitions. It's ok, I can do what I want but...

on reboot, there is a Superblock problem, something like that. When I check with xfs_check :

xfs_check: unexpected XFS SB magic number 0x00000000
xfs_check: read failed: Invalid argument
xfs_check: data size check failed
cache_node_purge: refcount was 1, not zero (node=0x681420)
xfs_check: cannot read root inode (22)
bad superblock magic number 0, giving up

So, I tried to delete the partition with parted, to recreate a new one. No problem. But when I mount the new partition, all the data that were on my deleted partition are there !!! That's of course not a problem, but I'm wondering if there's a way to have this partition work directly without having to delete and recreate it ?

I checked the /proc/partition before and after doing parted :

BEFORE
major minor #blocks name

104     0   35532720 cciss/c0d0
104     1   34025638 cciss/c0d0p1
104     2          1 cciss/c0d0p2
104     5    1502046 cciss/c0d0p5
105     0 7325417080 cciss/c1d0
105     1  [B]882966102[/B] cciss/c1d0p1

AFTER
major minor #blocks name

104     0   35532720 cciss/c0d0
104     1   34025638 cciss/c0d0p1
104     2          1 cciss/c0d0p2
104     5    1502046 cciss/c0d0p5
105     0 7325417080 cciss/c1d0
105     1 [B]7325417046[/B] cciss/c1d0p1

So, any idea what I could do ?

Thanks a lot
Amandine

On Tue, 6 Nov 2007 at 2:58pm, Amandine AUPETIT wrote

First guess -- did you use a gpt disklabel on that device? Standard (msdos) disklabels don't work on devices >2TB. The usual symptom of a big device with an msdos disklabel is that the partition table goes away on reboot.

Joshua Baker-LePain
QB3 Shared Cluster Sysadmin
UCSF

I second that hunch. :)

-Eric

Hi,
Thanks for the advice !
I checked the label with xfs_admin -l :

# xfs_admin -l /dev/cciss/c1d0p1
label = ""

I tried to blank it in case there is something invisible :

# xfs_admin -L -- /dev/cciss/c1d0p1
writing all SBs
new label = ""

But it seems to be the same. :(

Amandine

No, not the filesystem label, the disklabel, otherwise known as the partition table - dos vs. gpt. This is something you set with parted or fdisk, not xfs_admin.

-Eric

Ok, sorry for the mix-up.
You were right, the problem was about the partition table.
Actually, even if it was a gpt partition table, it was corrupted. I seems to be a ubuntu parted problem. I had to rebuild pared from the sources and when I ran it, it said :

# ./parted
GNU Parted 1.8.8
Using /dev/cciss/c1d0
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print                                                           print
Warning: /dev/cciss/c1d0 contains GPT signatures, indicating that it has a GPT
table.  However, it does not have a valid fake msdos partition table, as it
should.  Perhaps it was corrupted -- possibly by a program that doesn't
understand GPT partition tables.  Or perhaps you deleted the GPT table, and are
now using an msdos partition table.  Is this a GPT partition table?
Yes/No? yes                                                              yes
Model: Compaq Smart Array (cpqarray)
Disk /dev/cciss/c1d0: 7501GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt

Number Start End Size File system Name Flags
1 17.4kB 7501GB 7501GB xfs primary

So I deleted the existing partition and recreated a new one. I found back all my data on this new partition, and on reboot there is no problem anymore.

Thanks a lot for your help ! :)

Amandine

Wow, I love a happy ending, especially when it involves 7T of data ;-)

-Eric