topic Re: /etc/fstab in Operating System - HP-UX

/etc/fstab

subhashni — Fri, 15 Feb 2002 16:47:34 GMT

Hi
I acceidently commented out some of the file system in /etc/fstab.Now i could not boot the system.As well as i could boot in to single user mode using CD.What should i do?I need to
Change the entries in /etc/fstab and boot the system.Please help.

Re: /etc/fstab

Bill McNAMARA_1 — Fri, 15 Feb 2002 16:48:35 GMT

mount your filesystems one by one

mount -p > /etc/fstab

mount -p > /fstab.backup

Later,
Bill

Re: /etc/fstab

Sanjay_6 — Fri, 15 Feb 2002 16:50:05 GMT

Hi,

If you can boot into single user mode using the system itself, you can edit the /etc/fstab file and uncomment the entries and then reboot. If you have booted using the Cd, you'll have to mount the lvol3 to a temporary directory and then edit etc/fstab in that directory, unmount the lvol3, and reboot.

Hope this helps.

Regds

Re: /etc/fstab

subhashni — Fri, 15 Feb 2002 16:51:55 GMT

No.I can not get in to single user mode.Even when booting from CD

Re: /etc/fstab

Bill McNAMARA_1 — Fri, 15 Feb 2002 16:53:31 GMT

oh, sorry being too quick

if you can't boot into lvmmaintenance/single user

hpux -is -lm

and uncomment your modifs then you'll need to activate all the vgs via

vgchange -a y vg00
mount /dev/vg00/lvol1 /stand
mount /dev/vg00/lvol9 /var
mount /dev/vg00/lvol7 /usr
mount /dev/vg00/lvol4 /tmp
mount /dev/vg00/lvol6 /opt
mount /dev/vg00/lvol5 /home

vgchange -a y vg01
vgdisplay -v vg01 | grep Name
mount ..
mount ..
mount ..
(you can get hte vgnames from strings /etc/lvmtab)

and mount the lv's /filsystems individually.

mount -p will return a format compatable with the /etc/fstab.

Later,
Bill

Re: /etc/fstab

Helen French — Fri, 15 Feb 2002 16:54:27 GMT

Hi,

Boot in single user mode from the boot disk (why CD ?). At the ISL prompt:

ISL > hpux -is

OR, if you want LVM maintenance mode,

ISL> hpux -lq

Once booted from the bood disk, you will be able access /etc/fstab. Edit it and make the changes. If you kept a copy of the file, you can make use of that.

HTH,
Shiju

Re: /etc/fstab

Bill McNAMARA_1 — Fri, 15 Feb 2002 16:57:39 GMT

If it's an A,L or N you can take a disk from a working system, boot from it,
vgimport your failed disk,
mount the lvols,
repair the fstab, vgexport, replace the hardware, reboot.

Other than that, you should be able to mount your / from the rescue memory based system.

The device file will be strang, but you've got some limited commands in /sbin/

after mounting it, you can repair the fstab.

Strange that
hpux -is -lm
doesn't work....

Later,
Bill

Re: /etc/fstab

Helen French — Fri, 15 Feb 2002 16:57:45 GMT

Ooops ..sorry !

for lvm maintenance use 'hpux -lm'

'hpux -lq' for no quarum check

Shiju

Re: /etc/fstab

Sanjay_6 — Fri, 15 Feb 2002 17:06:45 GMT

Hi,

Try this procedure on booting into recovery mode,

http://us-support2.external.hp.com/cki/bin/doc.pl/sid=429a49f018e7cb972b/screen=ckiDisplayDocument?docId=200000047869323

Hope this helps.

Regds

Re: /etc/fstab

Sanjay_6 — Fri, 15 Feb 2002 17:08:23 GMT

Hi,

yopu can try the lvm maintainance mode suggested by bill and shiju first. If that doesn't help then try the link posted by me.

Hope this helps.

Regds

Re: /etc/fstab

subhashni — Fri, 15 Feb 2002 17:24:51 GMT

Guys,
I could not boot from disk even to single user mode.If I boot from cdrom like
boot P3
Interact with IPL>Y
IPL>hpux -lm

Is this right?or please tell me the further steps.I lost myself in the tension.
Thanks

Re: /etc/fstab

Sanjay_6 — Fri, 15 Feb 2002 17:33:57 GMT

Hi Subhashni,

try this,

boot the system, interrupt the boot process.

type "bo pri"

Select y to interact with ipl. at the ipl prompt type

ipl> hpux -lm (;0)/stand/vmunix

this will boot the system into lvm maintainance mode. Edit /etc/fstab. save the file and reboot. don't do a shutdown over here.

If this does not work. Boot the system using the core os cd, at the install menu, choose to interact with the recovery cell and then follow the pocedure outline in the link i had posted earlier. If you are unable to open the link, i can post it as a text attachement. Let me know if you want us to post it as a text attachement and if you are unable to open the link.

Hope this helps.

regds

Re: /etc/fstab

Helen French — Fri, 15 Feb 2002 17:34:22 GMT

Hi,

boot from the disk itself. You don't need to use the Recovery CD now. Boot from the root disk - interact with ISL - hpux -lm.

As a next step, you can try booting from the OLD kernel, if you suspect that as a problem. /stand/vmunix.prev

HTH,
Shiju

Re: /etc/fstab

subhashni — Fri, 15 Feb 2002 17:38:11 GMT

Yes.sanjay.You are right.I could not open the link.CAn pls send the text.Thanks for the help.

Re: /etc/fstab

Sanjay_6 — Fri, 15 Feb 2002 17:39:23 GMT

Hi Subhashni,

Here is the doc in text format

hope this helps.

Regds

Re: /etc/fstab

subhashni — Fri, 15 Feb 2002 19:14:08 GMT

Hi sanjay
I could not open the text message also.Can you please cut and paste in reply itself.That will
be very helpful for me.
Thanks

Re: /etc/fstab

Sanjay_6 — Fri, 15 Feb 2002 19:40:48 GMT

Hi Subhashni,

Here is the doc, I've edited it to make it a little smaller

//Quote//
How do I boot my system from Support Media on 11.00 ?
DocId: OZBEKBRC00000582
Updated: 1/28/00 11:06:37 AM

PROBLEM : My system won't boot due to problems with the LIF area, a missing kernel, or other missing files on my system.

RESOLUTION

FOR HPUX 11.XX ---------

Activate an LVM Root Volume Group from the Install/Support Media on a 11.00 system with 24MB of memory or more

This document details how to access your LVM Root Volume Group from the Install/Support Media at 11.00.

NOTE
1. Boot from the Install/Support Media.
Boot from the path of the CD media and do NOT interact with ISL.
You will get a menu with the following options:

Install HP-UX
Run a recovery shell
Advanced Options

2. Select "Run a Recovery Shell" from the menu.

3. Enter x from the SUPPORT MEDIA MAIN MENU, to exit to the shell.

4. Type chroot_lvmdisk. Something similar to the following will be displayed:

Enter the hardware path associated with the '/'(ROOT) file system (example: 7.6.9.37 )

5. Type to accept the example (default) as your root file system hardware path; otherwise, enter the hardware path for the root file system hardware you wish to specify in its place.

6. If you type , the following will be displayed:

Is 7.6.9.37 the hardware path of the root/boot disk?[y|n|q]-

7. Enter y, and something similar to the following will be displayed:
If your disk IS an LVM disk, you will see the following:

/sbin/fs/hfs/fsck -c 0 -y /dev/rdsk/c2t1d0s2lvm

** /dev/rdsk/c2t1d0s2lvm
** Last Mounted as /
** Phase 1 - Check Blocks and Sizes
** Phase 2 - Check Pathnames
** Phase 3 - Check Connectivity
** Phase 4 - Check Reference Counts
** Phase 5 - Check Cyl groups
6256 files, 0 icont, 1494 used, 1563824 free (928 frags, 195362 blocks)

/sbin/fs/hfs/mount /dev/dsk/c2t1d0s2lvm /ROOT
/sbin/fs/hfs/mount /dev/dsk/c2t1d0s1lvm /ROOT/stand

loading /usr/sbin/chroot
x ./usr/sbin/chroot 123456 bytes 96 blocks

Enter 'cd /ROOT; chroot /ROOT /sbin/sh' at the shell prompt to chroot to the customer's /(root) disk.

(NOTE: If this command fails with a "bad superblock.." message, your boot disk may not be an LVM disk.
If so, try: fsck /dev/rdsk/c2t1d0 (use your special file!)
If you see fsck messages akin to those above, you are making progress and your disk is NOT an LVM disk.)

8. Enter cd ROOT; chroot /ROOT /sbin/sh at the shell prompt.

9. Enter vgchange -a y /dev/vg00.

This will "activate" vg00, so that you can get to your swap area, /usr, etc.

Mount /usr.

10. Enter vgdisplay -v at the prompt.

The logical volumes within the disk corresponding to the various components (/stand, swap, /, /home, /opt, /tmp, /usr, /var) are listed.

You must know which lvol is for swap (usually lvol2), which lvol is for /usr (usually lvol6), etc.

11. Enter the swapon command; for example, swapon /dev/vg00/lvol2.

Usually, install makes lvol2 your swap area with a default value of 48mb, but you must know which lvol is actually your swap area.

Executing this command will yield the error no room in system tables to add paging to lvol2, but this just means that it couldn't configure all the swap in lvol2; however, enough swap is configured to prevent possible memory faults caused by lack of swap.

12. Enter fsck /dev/vg00/rlvol6; that is, use the lvol number where /usr resides. (You may have to umount /dev/vg00/lvol6)

13. Enter the mount command; e.g., mount /dev/vg00/lvol6 /usr.

14. Repeat steps 12 and 13 for /var and /tmp.

You can now repair any file damage that has occurred.

//Endquote//

Hope this helps.

Regds

Re: /etc/fstab

subhashni — Fri, 15 Feb 2002 21:29:54 GMT

Thanks.It will work i hope.But Iwas asked to run fsck on device which carries root file system.If i do ,It says that run with -b option.To run -b
option I need alternate superblock.What should i do?Thanks.

Re: /etc/fstab

Sanjay_6 — Fri, 15 Feb 2002 21:38:13 GMT

Hi Subhashni,

your root should be vxfs, so instead of using

/sbin/fs/hfs/fsck -c 0 -y /dev/rdsk/c2t1d0s2lvm

Use,
/sbin/fs/vxfs/fsck -c 0 -y /dev/rdsk/c2t1d0s2lvm

while mounting the root, use the vxfs mount to mount /

Hope this helps.

Regds

Re: /etc/fstab

subhashni — Fri, 15 Feb 2002 21:55:09 GMT

Hi
I have attached the messages below

#/sbin/fs/vxfs/fsck /dev/rdsk/c0t5d0
invalid super-block
vxfs fsck: cannot initialize aggregate
file system check failure, aborting ...

# fsck -y /dev/rdsk/c0t5d0
** /dev/rdsk/c0t5d0
BAD SUPER BLOCK: MAGIC NUMBER WRONG
USE -b OPTION TO FSCK TO SPECIFY LOCATION OF AN ALTERNATE
SUPER-BLOCK TO SUPPLY NEEDED INFORMATION; SEE fsck(1M).

If time permits please reply me.I appreciate you like anything.
Thanks.