System recovery techniques

            System Recovery Techniques

How to check running and stop services at run level :

# cd /etc/rc5.d        // To check at run level 5
# ls -ltr

Output :
K01......
K02......
K03......
.........
.........
.........
.........
S01......
S02......
.........
.........
K = Kill, service will be stopped on the current run level
S = Start, service will start on the current run level

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Condition 1 : /etc/fstab is corrupted, how to recover

Entry of /boot file system is corrupted in /etc/fstab file

1.    Insert the Rescue disk
2.    continue
3.    ok
4.    Shell start --- Enter
5.    # chroot /mnt/sysimg
6.    # mount -o remount /        ['/' rewritable form]
7.     exit
8.    exit
9.    reboot reboot

Condition 2 : To Recover /etc/passwd


1.    Insert the Rescue disk
2.    continue
3.    ok
4.    Shell start --- Enter
5.    # chroot /mnt/sysimg
6.    # cd /etc
7.    # ls                [to view 'passwd-' file]
8.    # cp -p passwd - /etc/passwd    [-p = with permission]
9.     exit
10.    exit
11.    reboot reboot

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