Re: Data Offset
From: NeilBrown <hidden>
Date: 2012-06-01 23:52:37
On Fri, 1 Jun 2012 18:22:33 -0500 freeone3000 [off-list ref] wrote:
Hello. I have an issue concerning a broken RAID of unsure pedigree. Examining the drives tells me the block sizes are not the same, as listed in the email.quoted
I certainly won't be easy. Though if someone did find themselves in that situation it might motivate me to enhance mdadm in some way to make it easily fixable.I seem to be your motivation for making this situation fixable. Somehow I managed to get drives with an invalid block size. All worked fine until a drive dropped out of the RAID5. When attempting to replace, I can re-create the RAID, but it cannot be of the same size because the 1024-sector drives are "too small" when changed to 2048-sector, exactly as described. Are there any recovery options I could try, including simply editing the header?
You seem to be leaving out some important information. The "mdadm --examine" of all the drives is good - thanks - but what exactly if your problem, and what were you trying to do? You appear to have a 5-device RAID5 of which one device (sde3) fell out of the array on or shortly after 23rd May, 3 drives are working fine, and one - sdf (not sdf3??) - is a confused spare.... What exactly did you do to sdf? NeilBrown
mdadm --examine of all drives in the RAID:
/dev/sdb3:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 9759ad94:75e30b6b:8a726b4d:177a6eda
Name : leyline:1 (local to host leyline)
Creation Time : Mon Sep 12 13:19:00 2011
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 3906525098 (1862.78 GiB 2000.14 GB)
Array Size : 15626096640 (7451.10 GiB 8000.56 GB)
Used Dev Size : 3906524160 (1862.78 GiB 2000.14 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 872097fa:3ae66ab4:ed21256a:10a030c9
Update Time : Fri Jun 1 03:11:54 2012
Checksum : 6d627f7a - correct
Events : 2127454
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 1
Array State : AAAA. ('A' == active, '.' == missing)
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 9759ad94:75e30b6b:8a726b4d:177a6eda
Name : leyline:1 (local to host leyline)
Creation Time : Mon Sep 12 13:19:00 2011
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 3906525098 (1862.78 GiB 2000.14 GB)
Array Size : 15626096640 (7451.10 GiB 8000.56 GB)
Used Dev Size : 3906524160 (1862.78 GiB 2000.14 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 2ea285a1:a2342c24:ffec56a2:ba6fcf07
Update Time : Fri Jun 1 03:11:54 2012
Checksum : fae2ea42 - correct
Events : 2127454
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 0
Array State : AAAA. ('A' == active, '.' == missing)
/dev/sdc3:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 9759ad94:75e30b6b:8a726b4d:177a6eda
Name : leyline:1 (local to host leyline)
Creation Time : Mon Sep 12 13:19:00 2011
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 3906525098 (1862.78 GiB 2000.14 GB)
Array Size : 15626096640 (7451.10 GiB 8000.56 GB)
Used Dev Size : 3906524160 (1862.78 GiB 2000.14 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 2ea285a1:a2342c24:ffec56a2:ba6fcf07
Update Time : Fri Jun 1 03:11:54 2012
Checksum : fae2ea42 - correct
Events : 2127454
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 0
Array State : AAAA. ('A' == active, '.' == missing)
/dev/sdd3:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 9759ad94:75e30b6b:8a726b4d:177a6eda
Name : leyline:1 (local to host leyline)
Creation Time : Mon Sep 12 13:19:00 2011
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 3906524160 (1862.78 GiB 2000.14 GB)
Array Size : 15626096640 (7451.10 GiB 8000.56 GB)
Data Offset : 1024 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 8d656a1d:bbb1da37:edaf4011:1af2bbb9
Update Time : Fri Jun 1 03:11:54 2012
Checksum : ab4c6863 - correct
Events : 2127454
Layout : left-symmetric
Chunk Size : 512K
Device Role : Active device 3
Array State : AAAA. ('A' == active, '.' == missing)
/dev/sde3:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 9759ad94:75e30b6b:8a726b4d:177a6eda
Name : leyline:1 (local to host leyline)
Creation Time : Mon Sep 12 13:19:00 2011
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 3906524160 (1862.78 GiB 2000.14 GB)
Array Size : 15626096640 (7451.10 GiB 8000.56 GB)
Data Offset : 1024 sectors
Super Offset : 8 sectors
State : clean
Device UUID : 37bb83bd:313c9381:cabff9d0:60bd205c
Update Time : Wed May 23 03:30:50 2012
Checksum : f72e6959 - correct
Events : 2004256
Layout : left-symmetric
Chunk Size : 512K
Device Role : spare
Array State : AAAA. ('A' == active, '.' == missing)
/dev/sdf:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 9759ad94:75e30b6b:8a726b4d:177a6eda
Name : leyline:1 (local to host leyline)
Creation Time : Mon Sep 12 13:19:00 2011
Raid Level : raid5
Raid Devices : 5
Avail Dev Size : 3907027120 (1863.02 GiB 2000.40 GB)
Array Size : 15626096640 (7451.10 GiB 8000.56 GB)
Used Dev Size : 3906524160 (1862.78 GiB 2000.14 GB)
Data Offset : 2048 sectors
Super Offset : 8 sectors
State : clean
Device UUID : e16d4103:cd11cc3b:bb6ee12e:5ad0a6e9
Update Time : Fri Jun 1 03:11:54 2012
Checksum : e287a82a - correct
Events : 0
Layout : left-symmetric
Chunk Size : 512K
Device Role : spare
Array State : AAAA. ('A' == active, '.' == missing)
--
James Moore
--
James Moore
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