fsck

[Otto Folprecht]

Hi, I need to take the system down into sigle mode. When I do that I need to run fsck on the /var and /usr. Since the only way to do that is to crash the system (the story is long why) what is the correct syntax for the fsck command to recover /var and /usr. THX Otto

[Paul Eadington_1]

fsck -F {filesystem_type} -o {options} /dev/vg??/lvol??

Assuming your /var was /dev/vg00/lvol7, is a vxfs filesystem and you wanted to do a full check.

fsck -F vxfs -o full -y /dev/vg00/lvol7

The -y assumes a yes response to any prompts that would be flagged.

try man fsck to see the full list of options.

Hope this helps.

[A. Clay Stephenson]

Well, the first thing to do is a 'bdf' command to identify the devices associated with those filesystems or do a cat /etc/fstab. The cat /etc/fstab should also tell you the type of filesystem: vxfs (most likely) or hfs.

Here is an example:
fsck -F vxfs -y /dev/vg00/rlvol7

man mount_vxfs for details.

I assume you have lost the root passwd.

[Hoang Chi Cong_1]

Hi Otto
You can follow these steps:

1. mount -v
Start this command to determine which file systems are mounted where.
For example:
/dev/vg00/lvol8 on /var type vxfs delaylog on Sun Dec 19 03:39:02 2003
/dev/vg00/lvol7 on /usr type vxfs delaylog on Sun Dec 19 03:39:02 2003

2. umount /dev/vg00/filesystem
umount /dev/vg00/lvol8
umount /dev/vg00/lvol7
fsck should be run on quiescent file systems; unmount the file system before proceeding.
3. fsck -F -y vxfs /dev/vg00/lvol8
or : fsck -F -y hfs /dev/vg00/lvol7
This depend on what kind of your filesystem...

4. Remount the filesystem
mount /dev/vg00/lvol8
mount /dev/vg00/lvol7
Once fsck completes, remount the file system(s).
5. Restore any corrupted files.
In order to fix file system corruption, fsck may have to remove one or more files. Watch for "REMOVE" messages in the fsck output, and be sure to restore the affected files from tape.fsck may also RECONNECT orphaned files. If you see any RECONNECT messages, check the file systemâ s lost+found directory. The next slide discusses the lost+found directory in greater detail.


Hope this helps
regard,
HoangChiC

[Nguyen Anh Tien]

Full syntax of fsck is
/usr/sbin/fsck [-F FSType] [-m] [-V] [special ...]
/usr/sbin/fsck [-F FSType] [-o FSspecific-options] [-V] [special ...]
In order to determine FStype you check
#cat /etc/fstab
[ipcaspa:/] cat /etc/fstab
/dev/vg00/lvol3 / vxfs delaylog 0 1
/dev/vg00/lvol1 /stand hfs defaults 0 1
/dev/vg00/lv_swap1 ... swap pri=0 0 0
/dev/vg00/lvol4 /tmp vxfs delaylog 0 2
/dev/vg00/lvol5 /home vxfs delaylog 0 2
/dev/vg00/lvol6 /opt vxfs delaylog 0 2
/dev/vg00/lvol7 /usr vxfs delaylog 0 2
/dev/vg00/lvol8 /var vxfs delaylog 0 2
#/dev/vg00/lvtux /home/tux6.5 vxfs rw,suid,nolargefiles,delaylog,datainlog 0 2
/dev/vg00/lvora /home/oracle vxfs rw,suid,nolargefiles,delaylog,datainlog 0 2
/dev/vg00/lvkeb /keb vxfs rw,suid,nolargefiles,delaylog,datainlog 0 2
/dev/vg00/lv_swap2 ... swap pri=0 0 2
-m : sanity check only
In order to get special you pay attention on first field of /etc/fstab
2. You want fsck check /var. just type (/var must not be mounted)
#fsck -F vxfs -m /dev/vg00/lvol8

[Michael D. Zorn]

If you have hfs, the "fsck -F hfs /dev/vg00/rlvol12" (or whatever) will either finish quickly and report something like "file system clean", or it will go into a sequence of error messages, after each one, "CLEAR?" or "FIX" (or something like that). Reply "y" to each. Don't forget the "r" in "rlvolNN"

The worst case is when it says "bad superblock - try another one". You can try "-b 16" (that's our usual default alternate superblock), but even if that works, it's not really reliable (my experience).

Sometimes there will be hundreds of the "CLEAR?" (or "FIX?") messsages. If you find more than a dozen or so, run fsck with "-y" (reply Y to all of them). This is sort of a last resort. I used it a while ago ; the fsck ran overnight (probably 6 to 8 hours), and when it was done, a regular fsck reported OK, but the data was gone.

In that case, it would have been quicker to do a newfs followed by a restore.

I hope you can recover to where you can do a regular "shutdown"