Recover SCSI disks

Recover SCSI disks

[Robin Bowes]

Hi,

I've got a Compaq U2 storage array connected to a Compaw Smart 2/p
controller with an assortment of 4.3GB and 9.1GB disks that I use for
testing purposes.

Some of the drives have "died" on me, i.e. I get yellow lights when they
are plugged into the arrays.

Is it possible to do anything low-level to ressurect these drives? e.g.
take them out of their caddies, connected them directly to a SCSI
controller and low-level format them or something?

(There's no data on them - I just want them to work again!)

Any suggestions appreciated.

R.
-- 
http://robinbowes.com

If a man speaks in a forest,
and his wife's not there,
is he still wrong?

Re: Recover SCSI disks

[Douglas Gilbert]

Robin Bowes wrote:
> Hi,
> 
> I've got a Compaq U2 storage array connected to a Compaw Smart 2/p
> controller with an assortment of 4.3GB and 9.1GB disks that I use for
> testing purposes.
> 
> Some of the drives have "died" on me, i.e. I get yellow lights when they
> are plugged into the arrays.
> 
> Is it possible to do anything low-level to ressurect these drives? e.g.
> take them out of their caddies, connected them directly to a SCSI
> controller and low-level format them or something?
> 
> (There's no data on them - I just want them to work again!)
> 
> Any suggestions appreciated.

Robin,
You may like to fetch sg3_utils and try sg_format thus:
   sg_format /dev/sda
assuming a disk you have fetched from the array is placed
at /dev/sda .

If that fails, the disk is probably dead. Otherwise it
should tell you several things (and doesn't change
anything). Often drives in RAIDs are formatted
to a sector size slightly greater than 512 bytes. To
re-use the disk (freestanding) in linux you will need to
format it back 512 bytes thus:
   sg_format --format --size=512 /dev/sda

A format may not be needed. In any case, the next step
would usually be to partition the disk (e.g. with fdisk)
then make a file system on one or more of its partitions
(e.g. with mkfs.ext3 ). The disk (or at least its partition)
should then be ready to mount and use.

Doug Gilbert

Re: Recover SCSI disks

[Robin Bowes]

Douglas Gilbert said the following on 21/10/2005 02:11:
> Robin,
> You may like to fetch sg3_utils and try sg_format thus:
>    sg_format /dev/sda
> assuming a disk you have fetched from the array is placed
> at /dev/sda .

Douglas,

THanks for the tip, I'll give it a go.

> If that fails, the disk is probably dead. Otherwise it
> should tell you several things (and doesn't change
> anything). Often drives in RAIDs are formatted
> to a sector size slightly greater than 512 bytes. To
> re-use the disk (freestanding) in linux you will need to
> format it back 512 bytes thus:
>    sg_format --format --size=512 /dev/sda
> 
> A format may not be needed. In any case, the next step
> would usually be to partition the disk (e.g. with fdisk)
> then make a file system on one or more of its partitions
> (e.g. with mkfs.ext3 ). The disk (or at least its partition)
> should then be ready to mount and use.

Thanks again,

R.
-- 
http://robinbowes.com

If a man speaks in a forest,
and his wife's not there,
is he still wrong?

Re: Recover SCSI disks

[Robin Bowes]

Douglas Gilbert said the following on 21/10/2005 02:11:
> Robin,
> You may like to fetch sg3_utils and try sg_format thus:
>    sg_format /dev/sda
> assuming a disk you have fetched from the array is placed
> at /dev/sda .

Hmm, sg3_utils doesn't seem to contain sg_format:

[root@compact ~]# rpm -ql sg3_utils
/usr/bin/scsi_devfs_scan
/usr/bin/sg_dd
/usr/bin/sg_inq
/usr/bin/sg_logs
/usr/bin/sg_map
/usr/bin/sg_modes
/usr/bin/sg_rbuf
/usr/bin/sg_read
/usr/bin/sg_readcap
/usr/bin/sg_reset
/usr/bin/sg_scan
/usr/bin/sg_senddiag
/usr/bin/sg_start
/usr/bin/sg_test_rwbuf
/usr/bin/sg_turs
/usr/bin/sginfo
/usr/bin/sgm_dd
/usr/bin/sgp_dd
(man pages snipped)

Any idea where to find it?

R.
-- 
http://robinbowes.com

If a man speaks in a forest,
and his wife's not there,
is he still wrong?

Re: Recover SCSI disks

[Robin Bowes]

Robin Bowes said the following on 21/10/2005 12:38:
> Douglas Gilbert said the following on 21/10/2005 02:11:
> 
>> Robin,
>> You may like to fetch sg3_utils and try sg_format thus:
>>    sg_format /dev/sda
>> assuming a disk you have fetched from the array is placed
>> at /dev/sda .
> 
> 
> Hmm, sg3_utils doesn't seem to contain sg_format:
> 
> [root@compact ~]# rpm -ql sg3_utils
> /usr/bin/scsi_devfs_scan
> /usr/bin/sg_dd
> /usr/bin/sg_inq
> /usr/bin/sg_logs
> /usr/bin/sg_map
> /usr/bin/sg_modes
> /usr/bin/sg_rbuf
> /usr/bin/sg_read
> /usr/bin/sg_readcap
> /usr/bin/sg_reset
> /usr/bin/sg_scan
> /usr/bin/sg_senddiag
> /usr/bin/sg_start
> /usr/bin/sg_test_rwbuf
> /usr/bin/sg_turs
> /usr/bin/sginfo
> /usr/bin/sgm_dd
> /usr/bin/sgp_dd
> (man pages snipped)

Let me re-phrase that, the Fedora Core 4 sg3_utils-1.06-5 rpm doesn't 
contain sg_format (the above listing is from there).

I see from rpmfind that it is in the mandrake sg3_utils-1.16-1mdk rpm.

Ah, I've got the latest version from http://sg.torque.net/sg/index.html

R.
-- 
http://robinbowes.com

If a man speaks in a forest,
and his wife's not there,
is he still wrong?