Lost data on reiserfs

xgreen · 05-27-2006, 01:01 PM

hi,

I have formatted one 20GB harddisk with reiserfs & copy all my data onto it. After reboot the harddisk can't be accessed anymore. Anyway to recover the data? Below are the step taken,

umount /dev/hdb
mkreiserfs -f /dev/hdb
mount the drive and start copy all the data onto it. check the data on /dev/hdb found all ok.
reboot & .....

dmesg output :

Code:

      ide0: BM-DMA at 0xfc00-0xfc07, BIOS settings: hda:DMA, hdb:DMA
hdb: Maxtor 2B020H1, ATA DISK drive
hdb: max request size: 128KiB
hdb: 40020624 sectors (20490 MB) w/2048KiB Cache, CHS=39703/16/63, UDMA(100)
hdb: cache flushes not supported
 hdb: unknown partition table
ReiserFS: hdb: found reiserfs format "3.6" with standard journal
hdb: dma_intr: status=0x51 { DriveReady SeekComplete Error }
hdb: dma_intr: error=0x40 { UncorrectableError }, LBAsect=29622272, sector=29622272
end_request: I/O error, dev hdb, sector 29622272
ReiserFS: hdb: warning: sh-2029: reiserfs read_bitmaps: bitmap block (#3702784) reading failed
ReiserFS: hdb: warning: jmacd-8: reiserfs_fill_super: unable to read bitmap
hdb: dma_intr: status=0x51 { DriveReady SeekComplete Error }
hdb: dma_intr: error=0x40 { UncorrectableError }, LBAsect=29884416, sector=29884416
end_request: I/O error, dev hdb, sector 29884416
hdb: dma_intr: status=0x51 { DriveReady SeekComplete Error }

fdisk output :

Code:

[root@home ~]# fdisk -l /dev/hdb

Disk /dev/hdb: 20.4 GB, 20490559488 bytes
16 heads, 63 sectors/track, 39703 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes

Disk /dev/hdb doesn't contain a valid partition table

J.W. · 05-27-2006, 03:59 PM

After you ran mkreiserfs, you didn't define any partitions, and I'm assuming that when you said you mounted the drive you ran "mount /dev/hdb <mountpoint>".

You will need to create your partitions prior to mounting them, and the mount command should always refer to a specific partition rather than the device itself. Assuming that you created one partition that occupied the entire drive, the correct mount instruction would be

Code:

mount /dev/hdb1 <mountpoint>

where <mountpoint> is the actual mount point, eg, /mnt/backup or whatever

After that, your copy command should work. Good luck with it

Emerson · 05-27-2006, 04:18 PM

Everything J.W. said is correct indeed. However, a disk can be used without partition table, just by creating a filesystem on it as you did. At least ext3 works in such an unconventional way. Don't know about Reiser (which IMO is a lousy filesystem anyway).

xgreen · 05-27-2006, 06:07 PM

thanks for the reply. It is my intention to create the whole harddisk as one partition. I saw a warning when i gave "mkreiserfs /dev/hdb" but repeat the command with "-f" option. I not sure whether we can format the whole harddisk as one partition.

Emerson · 05-27-2006, 06:14 PM

You need to create that one partition first with fdisk, then you can create a filesystem on it.