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linux lvm2 boot / drive error [SOLVED]

Posted: Tue Aug 15, 2017 2:06 pm
by jackcq

yesterday when I started my computer, my Linux Mint 17.3 system refused to boot up,
spilling out the following errors:

Code: Select all

ata5.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
ata5.00: BMDMA stst 0x24
ata5.00: failed command : READ DMA EXT
ata5.00: cmd 25/00:08:68:20:75 /00:00:7c:00:00/e0 tag 0 dma 4096 in res 51/40:00:68:20:75/40:00:7c:00:00/00 Emask 0x9 (media error)
ata5.00: Status: {DRDY ERR}
ata5.00: error : {UNC}
blk_update_request: I/O error, dev sda, sector 208850792
Buffer I/O error on dm-2 logical block 13, asyn page read
I think, it's safe to say that it's a hardware error and that the harddrive is probably dead. Interestingly, only the linux LVM2 partition seems to
be affected, though. The system is dual boot with Win7 and there seems to be no problem with the Windows partitions whatsoever.
I've used the opportunity to migrate to Mint 18.2 on a new disk, but I am wondering if there's any way to look into the damaged partition
any further, and maybe recover some of the data on that LVM partition? I have most of the data on backup, but if there's anything I can
do, to check the drive and recover data, before tossing it away I would be grateful for hints. Thanks in advance.

Re: linux lvm2 boot / drive error

Posted: Tue Aug 15, 2017 6:34 pm
by syg00
Have a look at ddrescue - it will read the lv and recover what it can without stressing the drive. then return to concentrate on bad areas. Make sure to use the log file option.

Re: linux lvm2 boot / drive error

Posted: Thu Aug 17, 2017 9:18 am
by jackcq
Wow, thanks for the hint. It really worked, it took whole night, but I could copy over everything except a few kilobytes in bad sectors. Afterwards, I could activate the group with vgchange, and fix the filesystem with e2fsck on the new drive. One would have thought, that after some 20 years with linux, I would know know about the most important GNU utils, but this one completely slipped under my radar. Thanks again.