[ale] please, please help with scsi problem

[Transam]

> I mailed earlier, I think I've got a bad hard drive and VA Linux won't
> support it.  They flat refuse to help me trouble shoot b/c I am not
> running the kernel they shipped with (which has problems).

Clearly, VA Linux's financial woes is affecting their attitude.  Pity.

> I'm getting I/O errors on a device that I believe to be my primary hard
> drive.  Can anyone help me figure out how to list what devices my
> machine sees??  I am experiencing a definite degradation in performance
> in the last day or so, and a major upswing in errors reported that look
> like this:

     cat /proc/scsi/scsi

Then match up what you see to the known devices.  The following will help:

     dmesg | more

> Sep  5 11:36:04 acheron kernel: scsi0: ERROR on channel 0, id 1, lun 0,
> CDB: Read (10) 00 01 b0 a3 a8 00 00 08 00 
> Sep  5 11:36:04 acheron kernel: Info fld=0x1b0a3ac, Current sd08:04:
> sense key Medium Error
> Sep  5 11:36:04 acheron kernel: Additional sense indicates Unrecovered
> read error
> Sep  5 11:36:04 acheron kernel:  I/O error: dev 08:04, sector 17043688

> Now, from what little I can tell, channel 0, id 1, lun 0 is my main HDD
> but I don't know.  This is a very heavily read/written device but it's
> only been running for 1 month.

> Please someone point me in the direction of what I should do!  I'm
> afraid if I reboot to clear memory (also having problems there) that I'm
> going to totally lose my machine....which is a production database
> server.  

Uh, backup your important data RIGHT NOW!  If that system does not have
a tape drive or second trusted disk, backup over the network.  Network
backups are discussed in my book and a script to do it comes with the CD.
(Shameless plug.)

Sometimes the tape head was just off a bit when it wrote a block of data
and rewriting the data will recover.  The following sometimes helps by
rewriting such flakey sectors (but carries risks too if writing is
unreliable):

     dd if=scd0 of=sd0 bs=512 conv=noerror

> jenn

Bob Toxen
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