Re: Crashed Drive, libata wedges when trying to recover data

[Greg Stark <gsstark@mit.edu>]

Alan Cox <alan@lxorguk.ukuu.org.uk> writes:

> > Jeff, do we really have to wait 30 seconds for a timeout? If the drive hits an unreadble spot I 
> > would have thought it would come back to us with a read error rather than timing out the command.
> 
> The drive will retry for a few seconds then fail. The failure now
> generates a SCSI medium error to the core scsi layer and it does like to
> issue a few retries. The default retry count for scsi is probably too
> high for SATA given the drive retries.

Certainly over an hour seems a little excessive:

$ time dd bs=512 count=1  if=/dev/sda4 of=/dev/null
dd: reading `/dev/sda4': Input/output error
0+0 records in
0+0 records out

real    67m59.382s
user    0m0.001s
sys     0m0.002s

bash-2.05b# time mount /dev/sda4 /u4
/dev/sda4: Input/output error
mount: you must specify the filesystem type

real    71m59.322s
user    0m0.000s
sys     0m0.004s
bash-2.05b# 

-- 
greg