Re: Need help to recover root filesystem after a power supply issue

Carlos E. R.
2019-07-10T18:28:04Z

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On 10/07/2019 17.02, Andrey Zhunev wrote:

> Ooops, I forgot to paste the error message from dmesg.
> Here it is:
>
> Jul 10 11:48:05 mgmt kernel: ata1.00: exception Emask 0x0 SAct 0x180000 SErr 0x0 action 0x0
> Jul 10 11:48:05 mgmt kernel: ata1.00: irq_stat 0x40000008
> Jul 10 11:48:05 mgmt kernel: ata1.00: failed command: READ FPDMA QUEUED
> Jul 10 11:48:05 mgmt kernel: ata1.00: cmd 60/00:98:28:ac:3e/01:00:03:00:00/40 tag 19 ncq 131072 in#012 res 41/40:00:08:ad:3e/00:00:03:00:00/40 Emask 0x409 (media error) <F>
> Jul 10 11:48:05 mgmt kernel: ata1.00: status: { DRDY ERR }
> Jul 10 11:48:05 mgmt kernel: ata1.00: error: { UNC }
> Jul 10 11:48:05 mgmt kernel: ata1.00: configured for UDMA/133
> Jul 10 11:48:05 mgmt kernel: sd 0:0:0:0: [sda] tag#19 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
> Jul 10 11:48:05 mgmt kernel: sd 0:0:0:0: [sda] tag#19 Sense Key : Medium Error [current] [descriptor]
> Jul 10 11:48:05 mgmt kernel: sd 0:0:0:0: [sda] tag#19 Add. Sense: Unrecovered read error - auto reallocate failed
> Jul 10 11:48:05 mgmt kernel: sd 0:0:0:0: [sda] tag#19 CDB: Read(16) 88 00 00 00 00 00 03 3e ac 28 00 00 01 00 00 00
> Jul 10 11:48:05 mgmt kernel: blk_update_request: I/O error, dev sda, sector 54439176
> Jul 10 11:48:05 mgmt kernel: ata1: EH complete
>
> There are several of these.
> At the moment ddrescue reports 22 read errors (with 35% of the data
> copied to a new storage). If I remember correctly, the LVM with my
> root partition is at the end of the drive. This means more errors will
> likely come... :(
>
> The way I interpret the dmesg message, that's just a read error.

"auto realocate failed" is important. Might indicate the realocation
area is full :-?

> I'm
> not sure, but maybe a complete wipe of the drive will even overwrite /
> clear these unreadable sectors.
> Well, that's something to be checked after the copy process finishes.

Run the SMART long test after you have made a copy, and watch specially
for the Current_Pending_Sector, Offline_Uncorrectable, and
Reallocated_Sector_Ct values. Then overwrite the entire disk with zeroes
and repeat the test. If the bad sector number increases, dump the disk.

--
Cheers / Saludos,

Carlos E. R.
(from 15.0 x86_64 at Telcontar)

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