topic Re: Recreate device files in /dev/vg01 after accidental delete ? in Operating System - HP-UX

Recreate device files in /dev/vg01 after accidental delete ?

Sammy_2 — Sat, 07 Feb 2004 18:03:38 GMT

How do one recreate character and block device files in /dev/vg01 after an accidental delete
of these files. I need to restore (both character and block) device files for rlvoracle and lvoracle ? So that i see the lvoracle logical volume when I do lvdisplay -v vg01 ?

Re: Recreate device files in /dev/vg01 after accidental delete ?

Chris Watkins_1 — Sat, 07 Feb 2004 18:38:58 GMT

You could export and re-import the vg, but this will work:

You need to know which lvol this is, if it isn't the only one
in vg01. You also need to know the vg minor number. # ll /dev/vg01/group
to be sure. Meantime, I'll assume "1" there as well.
(If you have multiple lvols in the vg, try and see what's missing.)

mknod /dev/vg01/rlvoracle c 64 0x010001
mknod /dev/vg01/lvoracle b 64 0x010001

That should get you going, assuming vg01 and first lvol is lvoracle,
and everything else is in its default configuration.

Re: Recreate device files in /dev/vg01 after accidental delete ?

Jeff Schussele — Sat, 07 Feb 2004 18:41:07 GMT

Hi Sam,

Assuming vg01 is the 0x010000 VG device AND lvoracle is the FIRST LV in the VG, then

cd /dev/vg01
mknod lvoracle b 64 0x010001
mknod rlvoracle c 64 0x010001

HTH,
Jeff

Re: Recreate device files in /dev/vg01 after accidental delete ?

Steven E. Protter — Sat, 07 Feb 2004 19:34:05 GMT

insf -e

Will fix that right up.

SEP

Re: Recreate device files in /dev/vg01 after accidental delete ?

Sridhar Bhaskarla — Sun, 08 Feb 2004 05:37:57 GMT

Hi Sam,

Look at /etc/lvmconf directory and see if you have a file called vg01.mapfile. If so, then do a 'cat vg01.mapfile' and note the logical volume number and the name. If may be something like

1 lvol1
2 lvol2

etc

You would need to know the minor number of the group file (ll /dev/vg01/group). If you don't have it, then you will need to create it. Hopefully you remember it or it is in the sequence

mknod /dev/vg01/group c 64 0x010000

Then create the logical volume device files using the following commands

mknod /dev/vg01/ c 64 0x01000

where lvol_name is the second field and lvol_number is the first field in /etc/lvmconf/vg01.mapfile file for each lvol.

If this didn't work, then you will need to export/re-import the VG which means unmounting the filesystems followed by deactivating the VG.

-Sri

Re: Recreate device files in /dev/vg01 after accidental delete ?

Sridhar Bhaskarla — Sun, 08 Feb 2004 13:17:56 GMT

Hmmmm.. correction in my previous message. Make sure you create block and character device files as mentioned by Jeff and others. You can use /etc/lvmconf/vg01.mapfile to obtain the lv names and numbers.

-Sri

Re: Recreate device files in /dev/vg01 after accidental delete ?

Sammy_2 — Sun, 08 Feb 2004 19:11:29 GMT

Thanks,Jeff, Chris. Both of yours method works best after i got the numbering from /etc/lvmconf/mapfile (as pointed out by Shridhar). Steve , I tried your method that did not create the device files. Thanks to all. I will assign points once my browser lets me do it.
Shridhar . Thanks for your help in getting me straight with detailed explanation.