I have a raid0 comprised of 4x identical 300Gb drives
Disk /dev/hdf: 300.0 GB, 300001443840 bytes
255 heads, 63 sectors/track, 36473 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x0009f25f
Device Boot Start End Blocks Id System
/dev/hdf1 * 1 36473 292969341 fd Linux raid
autodetect
md1 : active raid0 hdk1[0] hdg1[2] hdf1[1] hde1[3]
1171876864 blocks 256k chunks
hdf recently wobbled and the kernel happily dumped out the following
message (about 20 odd times)
hdf: dma_intr: status=0x51 { DriveReady SeekComplete Error }
hdf: dma_intr: error=0x40 { UncorrectableError }, LBAsect=216521307,
high=12, low=15194715, sector=216521303
ide: failed opcode was: unknown
end_request: I/O error, dev hdf, sector 216521303
terrific.
smartctl shows
5 Reallocated_Sector_Ct 0x0033 252 252 063 Pre-fail
Always - 16
196 Reallocated_Event_Count 0x0008 251 251 000 Old_age
Offline - 2
197 Current_Pending_Sector 0x0008 253 253 000 Old_age
Offline - 1
198 Offline_Uncorrectable 0x0008 252 252 000 Old_age
Offline - 1
so while a few sectors have been remapped the sector remapping table is
barely used, so I'm reasonably confident the disk is 'ok' in terms of
normal operation
Now my question about all this is how the hell do I determine what file
it was trying to access? (I just want to be sure that whatever file it
was fiddling with isn't a steaming pile of poo now)
normally if it were a single disk it would be reasonably straightforward
to work out what file was being used from debugfs: icheck <block>,
ncheck <inode from previews operation>
the issue I have with raid0 is, exactly what block should I be pointing
debugfs at since the kernel has given an absolute address on a physical
disk and no logical information as to where in the FS it was at the time ?
tune2fs -l /dev/md1
Block count: 292969216
Block size: 4096
mdadm --examine /dev/hdf1
/dev/hdf1:
Magic : a92b4efc
Version : 00.90.00
UUID : 2132d2e6:a2955ac2:6ad2f3dc:52b3dfd6
Creation Time : Wed May 26 18:34:06 2004
Raid Level : raid0
Used Dev Size : 292969216 (279.40 GiB 300.00 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 1
Update Time : Wed May 26 18:34:06 2004
State : active
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Checksum : bd5e5781 - correct
Events : 0.5
Chunk Size : 256K
Number Major Minor RaidDevice State
this 1 33 65 1 active sync /dev/hdf1
0 0 33 1 0 active sync /dev/hde1
1 1 33 65 1 active sync /dev/hdf1
2 2 34 1 2 active sync /dev/hdg1
3 3 34 65 3 active sync <---
empty. bug? (expected /dev/hdk1)
mdadm --version
mdadm - v2.6.2 - 21st May 2007
Would I be correct in assuming that I start my offset from hde1? do I
need some other funky math to account for striping/blocking?
Or I could just say 'to hell with it' and listen to elevator music all day.
Phil
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