Disk Geometry

Philip M. Gollucci pgollucci at p6m7g8.com
Tue Mar 8 13:45:25 PST 2005

Kevin Kinsey wrote:

> Dan Simmonds wrote:
>> I have a relatively new installation of FreeBSD 5.3 which I have been 
>> running
>> as a file server. Recently we had a power outage and when I booted up 
>> the
>> machine again, instead of a normal boot sequence I was given an 
>> "automount" prompt.
>> I understand that I have to mount a disk slice and fsck my hard drive 
>> (I think
>> this is right, please correct me if I'm wrong), only its been a while 
>> since I sliced
>> up my hard drive and I've forgotten what the disk looks like. Is 
>> there anyway
>> of investigating the disk geometry from this automount prompt? The only
>> commands I seem to have available are mount commands.
>> Thanks,
>> Dan.
> (Hi, Dan ... this probably needs to go over to questions at freebsd.org,
> where more experience folks will see it, so I'm redirecting the CC 
> there...)
> Ouch!  I hope your disk can recover.  Once you get this grassfire
> out, be sure and check your backup strategies....
> The *only* command you can enter isn't even really a command,
> it's simply the answer to the question "where the heck is /boot?"
> which is something the system desperately needs to know.
> IIRC (and who knows, it has been a little while since I saw this
> one, thank Deity) it gives you a hint or two about what to
> do.  The usual boot device is /dev/ad0s1 (for IDE drives) or
> /dev/da0s1 (for SCSI) and the filesystem type is normally
> ufs (but that could vary, ufs2 for example<?>).
> Once you get in, you will want to fsck and attempt to
> remount your slices; you probably won't have access to a lot
> of normal tools (for at least two reasons I can think of:
> one being that some of them are on the /usr partition,
> and the other being that $PATH is not set, so even stuff
> in /bin and /sbin will *say* "not found", just call 'em by the
> full path /sbin/fsck, /sbin/mount, etc.)  If everything fscks
> clean, try rebooting again to return to multi-user (normal)
> mode.
> Good luck.
> Kevin Kinsey
> _______________________________________________
> freebsd-questions at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-questions
> To unsubscribe, send any mail to 
> "freebsd-questions-unsubscribe at freebsd.org"

Being that this is a file server, its probably a good assumption that
he's using raid which would be ar0s1a by default.

specifically you'll want to do:

fsck /
mount /
swapon -a
/bin/cat /etc/fstab
for each of your partitions other then /
fsck /usr
fsck /tmp
... etc

mount -a
 [normal boot should continue]
If you don't want fsck to ask you questions you can use the fsck -y command
(answer yes to all questions)

Be sure the check the lost+found in the root of each slice for recovered 

Philip M. Gollucci
Senior Developer - Liquidity Services Inc.
Phone:  202.467.6868 x 268
E-Mail: pgollucci at liquidation.com
Web:    http://www.liquidation.com

More information about the freebsd-questions mailing list