Hi,
We have 8 disks (8x2TB=16TB) on an enclosure, with mdadm raid 6 serving ~12TB volume
from a SATA JBOD through 2 e-SATA ports to host machine. We used up 7 TB. One of e-SATA port
connecting 4 drives did not respond on controller, possibly due heat issues from adjacent video card
FX4800, or the controller momentarily went bad since we also had power glitches on multiple machines
at the same time. This incident made mdadm to report the 4 drives with "removed" status. After
relocating the card inside the machine and rebooting, all of the drives physically came up fine.
Now I was hoping to get 7 TB of data back, and I did:
#mdadm --assemble --scan
mdadm: /dev/md2 assembled from 4 drives - not enough to start the array.
Now I wanted to recover the data, so I did the following steps. I see
only 2 TB of 7 TB now when I mount. I know that data is still on drives
and I did not zero-superblock on any of the drives. How do I get data
back, reliably and quickly? Using mdadm v3.1.2 on FC14. Any pointers/suggestions
is very much appreciated. Thanks.
#mdadm -v --assemble --force /dev/md2 /dev/sd{b,c,d,e,f,g,h,i}
mdadm: looking for devices for /dev/md2
mdadm: /dev/sdb is identified as a member of /dev/md2, slot 0.
mdadm: /dev/sdc is identified as a member of /dev/md2, slot 1.
mdadm: /dev/sdd is identified as a member of /dev/md2, slot 2.
mdadm: /dev/sde is identified as a member of /dev/md2, slot 3.
mdadm: /dev/sdf is identified as a member of /dev/md2, slot 4.
mdadm: /dev/sdg is identified as a member of /dev/md2, slot 5.
mdadm: /dev/sdh is identified as a member of /dev/md2, slot 6.
mdadm: /dev/sdi is identified as a member of /dev/md2, slot 7.
mdadm: forcing event count in /dev/sdh(6) from 220810 upto 220815
mdadm: forcing event count in /dev/sdf(4) from 220809 upto 220815
mdadm: forcing event count in /dev/sdi(7) from 220809 upto 220815
mdadm: clearing FAULTY flag for device 4 in /dev/md2 for /dev/sdf
mdadm: clearing FAULTY flag for device 6 in /dev/md2 for /dev/sdh
mdadm: clearing FAULTY flag for device 7 in /dev/md2 for /dev/sdi
mdadm: added /dev/sdc to /dev/md2 as 1
mdadm: added /dev/sdd to /dev/md2 as 2
mdadm: added /dev/sde to /dev/md2 as 3
mdadm: added /dev/sdf to /dev/md2 as 4
mdadm: added /dev/sdg to /dev/md2 as 5
mdadm: added /dev/sdh to /dev/md2 as 6
mdadm: added /dev/sdi to /dev/md2 as 7
mdadm: added /dev/sdb to /dev/md2 as 0
mdadm: /dev/md2 has been started with 7 drives (out of 8).
# mdadm -D /dev/md2
/dev/md2:
Version : 0.90
Creation Time : Fri Dec 16 17:56:14 2011
Raid Level : raid6
Array Size : 11721086976 (11178.10 GiB 12002.39 GB)
Used Dev Size : 1953514496 (1863.02 GiB 2000.40 GB)
Raid Devices : 8
Total Devices : 7
Preferred Minor : 2
Persistence : Superblock is persistent
Update Time : Mon Mar 26 13:53:25 2012
State : clean, degraded
Active Devices : 7
Working Devices : 7
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
UUID : 4fcdcafa:fea0c196:4d5dd1d0:da2b21e5
Events : 0.220827
Number Major Minor RaidDevice State
0 8 16 0 active sync /dev/sdb
1 8 32 1 active sync /dev/sdc
2 8 48 2 active sync /dev/sdd
3 8 64 3 active sync /dev/sde
4 8 80 4 active sync /dev/sdf
5 0 0 5 removed
6 8 112 6 active sync /dev/sdh
7 8 128 7 active sync /dev/sdi
# mdadm /dev/md2 -a /dev/sdg
mdadm: re-added /dev/sdg
This step took 24 hrs to rebuild
#mdadm --stop
#mdadm --assemble --scan
where /etc/mdadm.conf has a line
ARRAY /dev/md2 level=raid6 num-devices=8 \
devices=/dev/sdb,/dev/sdc,/dev/sdd,/dev/sde,/dev/sdf,/dev/sdg,/dev/sdh,/dev/sdi
[yes no partitions, had been thsi way and has always worked]
#mount /dev/md2 /myarray
mounts fine, however, I now see only 2TB instead of 7 TB for /myarray. I need to get all of the data back and I am stuck here.
Sundar
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