[RAS] Nebka disk

[Thomas Krichel]

  Christian Zimmermann writes

> reboot
> # into 2.4 or 2.6?

  into 2.6, SECOND entry,
  
> #at reboot in grub: single user mode (select kernel, press "e", select kernel line, press "e", append "single" at the end of the line, "enter", press "b", root password)
>

  use the second entry, no editing required, I think. 


> 		   mount -o ro,remount /dev/sda1 

  Mount root disk read-only. Important.

> 
> e2fsck -c -y /dev/sda1
> 
> #according to the man page: 
> #   Note  that  in general it is not safe to run e2fsck on mounted filesys-
> #   tems.  The only exception is if the -n option is specified, and -c, -l,
> #   or  -L  options  are not specified.   However, even if it is safe to do
> #   so, the results printed by e2fsck are not valid if  the  filesystem  is
> #   mounted.    If e2fsck asks whether or not you should check a filesystem
> #   which is mounted, the only correct answer is "no".  Only experts  who
> #   really know what they are doing should consider answering this question
> #   in any other way.
> #I am no expert, in fact, I hardly understand what I am supposed to do here, 
> #are you sure you want to do this?
> 

  A read only mounted disk can be savely checked. Otherwise
  how would you check the file system

> # this takes a few hours.
> # what if something is wrong?

  The -y option will automatically take corrective action
  required

> 
> reboot
> 
> #single user again
> 
> rsync -va --exclude /vol --exclude /proc --exclude /sys / /vol
> 
> grub-install --directory /vol/boot/grub /dev/sdb1
> 
> # do you mean 
> #grub-install --root-directory=/vol/boot/grub /dev/sdb1
  
  Yes, sorry!

> # this is how I would understand it from the man page on nebka.
> # and why not use update-grub?

  That does a different thing, it updates the list of
  kernels that are available.
 
> #sdb1, not sdb, right?

  I think, but if it gripes try /dev/sdb instead.

> 
> #edit /vol/etc/fstab putting the right device for the swap, but how?

  I am not sure. Actually, there is a step missing, you need
  to format the disk. I will do this right now.

  Inspect and change partition table:

nebka:~# cfdisk /dev/sdb
nebka:~# 
nebka:~# 
nebka:~# 
nebka:~# mke2fs -j /dev/sdb1
mke2fs 1.40-WIP (14-Nov-2006)
/dev/sdb1 is mounted; will not make a filesystem here!
nebka:~# mount /dev/sdb1
mount: /dev/sdb1 already mounted or /vol busy
mount: according to mtab, /dev/sdb1 is already mounted on /vol
nebka:~# cd /vol
nebka:/vol# ls
lost+found  opt
nebka:/vol# cd
 
  I should have done this to start with:

nebka:~# umount /vol

  but it works like this too...


nebka:~# mke2fs -j /dev/sdb1
mke2fs 1.40-WIP (14-Nov-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
17924096 inodes, 35838999 blocks
1791949 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=0
1094 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872

Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 29 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.


nebka:~# mkswap /dev/sdb2
/dev/sdb2: No such device or address

  It does not like to do the swap, but the /dev/sdb2 is
  now earmarked for swap.

  It should be ok for you to let the partition table
  be as is, just comment out the part that mounts /dev/sdb
  Actually I did it for you.

nebka:~# cat /etc/fstab
# /etc/fstab: static file system information.
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
/dev/sda5       none            swap    sw              0       0
/dev/sda1       /               ext3    defaults,errors=remount-ro 0       1
/dev/hda        /media/cdrom    iso9660 ro,user,noauto  0       0
/dev/fd0        /media/floppy   auto    rw,user,noauto  0       0
/dev/hda        /cdrom          iso9660 ro,user,noauto  0       0
#/dev/sdb1      /vol            ext3    defaults        0       1


> And I suppose that file will be rsynched from /etc/fstab, right?

  Correct. If you switch the two disks, as you must do before the
  final boot, it will say that what now is /dev/sdb
  is what gets called /dev/sda, and the current configuration,
  which places the swap at the end should be just fine. 
 
  I will go to town now, later to the opera. I expert to 
  be back by 23:00 local time, your 13:00. If you start
  doing it then you can call me any time during the night,
  leave me a number and I'll call you right back to discuss
  the situation with you.

  Good luck!

  Cheers,

  Thomas Krichel                    http://openlib.org/home/krichel
                                RePEc:per:1965-06-05:thomas_krichel
  phone: +7 383 330 6813                       skype: thomaskrichel