On 12/05/2013 05:36 PM, Wilson Jonathan wrote:
On Thu, 2013-12-05 at 17:00 +0100, Bernd Schubert wrote:
On 12/05/2013 04:48 PM, Wilson Jonathan wrote:
Still the same problem, lists non partitioned space, unknown, unknown,
un partitioned.
I wonder if the problem is because i'm not re-creating it with bitmap
file, which is listed as starting 8 sectors from superblock, so with it
not being there the partition table is being read from this space and
not further along the space.
The bitmap is supposed to be in the gap between data and superblock.
Infact, looking at the re-created superblock there is a change...
/dev/sde6:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 1c413162:25c7b4af:7b305603:1ce49fed
Name : BorgCUBE:5 (local to host BorgCUBE)
Creation Time : Thu Dec 5 00:28:11 2013
Raid Level : raid6
Raid Devices : 6
Avail Dev Size : 1833309583 (874.19 GiB 938.65 GB)
Array Size : 3666617344 (3496.76 GiB 3754.62 GB)
Used Dev Size : 1833308672 (874.19 GiB 938.65 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
State : clean
Device UUID : de841586:f82b22ed:1a234ae7:57fbb36a
Update Time : Thu Dec 5 00:28:11 2013
Checksum : 9dcbeec1 - correct
Events : 0
Layout : left-symmetric
Chunk Size : 64K
The "data offset" is 262144 where as the sdc (original) is 2048
Seems to be a new mdadm version with different default values. Another
reason not to use '--create' unless there is really no other way. Try to
add --data-offset=1M.
My version of mdadm does not have --data-offset...
root@BorgCUBE:/mnt/datastore/wilsonjonathan# mdadm --create
--assume-clean --level=6 --raid-devices=6 --chunk=64
--data-offset=1M /dev/md5 /dev/sdd6 /dev/sde6 /dev/sdf6 /dev/sda6
missing missing
mdadm: unrecognized option '--data-offset=1M'
I also double checked the original, pre-corrupted, examine and found
that /dev/sdb6 had 1928 sectors (was a new 3tb drive, using a partition
on it, which had a slightly larger size, to replace the original
partition on a 1tb disk)
sda6:3, sdd6:0, sde6:1, sdf6:2 are all at 2048 sectors, so if I can
somehow create md5 using just these 4 disks it should be ok even if it
has no redundancy, assuming it works and I can get hold of a mdadm with
Sorry, I don't understand what you mean. sdb6 starts at 1928 sectors?
Assuming you have either 4k or 512B hw-sector disks that shouldn't make
a difference for alignment. If at all, I would correct it only once I
would have full redundancy.
offset (I have git, and have built from source before if it comes to
that... but a binary would be more helpful, or perhaps a mdadm that had
the original 2048 offset?) then clear the superblock from b and c and
re-add them to re-build the redundancy.
Well, I could probably build mdadm for you (if I should have the chroot
matching your distribution), but can't you just download an older or a
recent version for your distribution?
Cheers,
Bernd
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