topic Re: Device path in Operating System - Linux

Device path

peterchu — Wed, 05 May 2004 09:29:00 GMT

because the /tmp have problem when boot up , so I disable it in /etc/fstab , after bootup , the /tmp is disappeared , if I want to mount it back , what is the device path ( eg. /dev/sda2 ) of /tmp , how can I know it ? thx.

Re: Device path

Mark Grant — Wed, 05 May 2004 09:35:55 GMT

IT depends entirely on how it was set up. One way to guess would be to see which of your partitions seems not to be mounted with "df". Then try and mount it. It won't do any harm trying to mount a device if it doesn't exist. Test it on /mnt and then, if you find the right one, then put the entry back in fstab and re-boot.

You might be able to look through previous boot logs to see which devices have been mounted in the past. You can also use "fdisk" on your drives to see which partitions have linux filesystems on and compare this with what you already have mouned.

Don't expect to easily be able to mount it back on /tmp easily without a re-boot.

Re: Device path

peterchu — Wed, 05 May 2004 09:47:00 GMT

thx Mark,

this is my /etc/fstab

LABEL=/ / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
none /dev/pts devpts gid=5,mode=620 0 0
LABEL=/home /home ext3 defaults,usrquota 1 2
none /proc proc defaults 0 0
none /dev/shm tmpfs defaults 0 0
#LABEL=/tmp /tmp ext3 defaults 1 2
LABEL=/usr /usr ext3 defaults 1 2
LABEL=/var /var ext3 defaults 1 2
/dev/sda5 swap swap defaults 0 0
/dev/cdrom /mnt/cdrom iso9660 noauto,owner,kudzu,ro 0 0
/dev/fd0 /mnt/floppy auto noauto,owner,kudzu 0 0
~

because the /tmp can't be mount when boot , so i disable it ( as above ) ,
I tried to find it on the boot.log , but can't find it ,
besides the /users path also disappear after I have modified the /etc/fstab , is it possible mount it back without reboot ? thx.

Re: Device path

Mark Grant — Wed, 05 May 2004 09:56:24 GMT

Oh, OK,

If you are using the LABEL thing then you don't need to know what the device name is. You should be able to uncomment it and try "mount -a".

Two things though. Why did it stop working? and, on a running system, you may well find that /tmp (on the root filesystem) is in use and you therefore won't be able to mount anything on to it. You can try it but if it fails, you'll have to track down every process that has /tmp open and stop it before you will be able to mount /tmp again. A re-boot makes this task easier.

Re: Device path

Stuart Browne — Wed, 05 May 2004 18:00:20 GMT

Compare the output of 'mount' with your running system, and the output of 'fdisk -l /dev/sda'.

All the filesystems created as 'Linux' should have a mount point somewhere.

Re: Device path

peterchu — Wed, 05 May 2004 21:27:56 GMT

thx reply ,

may be my /tmp have problem , I tried to run fsck but fail , could suggest what can I do ?

# /sbin/fsck /tmp
fsck 1.27 (8-Mar-2002)
e2fsck 1.27 (8-Mar-2002)
fsck.ext2: Is a directory while trying to open /tmp

The superblock could not be read or does not describe a correct ext2
filesystem. If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193

Re: Device path

Stuart Browne — Wed, 05 May 2004 22:27:58 GMT

Show us the output of the following two commands:

cat /etc/fstab
mount

We'll say where to go next.

Re: Device path

V.Tamilvanan — Thu, 06 May 2004 03:55:31 GMT

Hi,
Currently your /tmp is not a FS it is a directory in the / FS (root FS). Because at the booting time the entry for /tmp was commented in /etc/fstab. So fsck will definitely fail.
You need to find the unmounted /tmp FS device file by comparing the fdisk, df and
mount outputs.

Re: Device path

Shaikh Imran — Thu, 06 May 2004 05:49:19 GMT

Hi,
First of all remove the # from the /tmp filesystem in fstab.
Go to single user mode via init 1
try to come in multiuser mode vi init 2 and then init 3 and see all the filesystems are getting mounted or not
if you are stuck at bcheckrc for /tmp then
use:
e2fsck -b 8193 /tmp

Regs

Re: Device path

Kiyoshi Miyake — Fri, 07 May 2004 04:18:02 GMT

Hi,

You should find the device name of /tmp by using follow command.

- find linux file system device

fdisk -l /dev/hda ( if you use SCSI disk, /dev/sda, etc. )

- find label=/tmp device

e2label /dev/hda1
e2label /dev/hda2 ...(result of fdisk ...)
:::

- fsck

e2fsck -y /dev/hda2 ( device name that you find bellow steps )

or recreate /tmp by mke2fs command.

Thanks.