How To Restore Root (and /usr/) rfile system Solaris- restoresymtable –

Sun Solaris – Restoring root file system (/) – Solaris 9, Solaris 10 provides steps we need to follow to restore the root file system (/ system) in SPARC and x86 (intel) machines.
1) Log in as root user. It is a security practice to login as normal user and perform an su to take root user (super user) role.
2) Appearance of # prompt is an indication that the user is root
3) Use who -a command to get information about current user
4) When / (root filesystem) is lost because of disk failure. In this case we boot from CD or from the network.
5) Add a new system disk to the system on which we want to restore the root (/) file system
6) Create a file system using the command :
newfs /dev/rdsk/partitionname
7) Check the new file system with teh fsck command :
fsck /dev/rdsk/partitionname
8) Mount the filesystem on a temporary mount point :
mount /dev/dsk/devicename /mnt
9) Change to the mount directory :
cd /mnt
10) Write protect the tape so that we can’t accidentally overwrite it. This is an optional but important step
11) Restore the root file system (/) by loading the first volume of the appropriate dump level tape into the tape drive. The appropriate dump level is the lowest dump level of all the tapes that need to be restored. Use the following command :
ufsrestore -rf /dev/rmt/n
12) Remove the tape and repeat the step 11 if there is more than one tape for the same level
13) Repeat teh step 11 and 12 with next ddump levels. Always begin with the lowest dump level and use highest ump level tape
14) Verify that file system has been restored :
15) Delete the restoresymtable file which is created and used by the ufsrestore utility :
rm restoresymtable
16) Change to the root directory (/) and unmount the newly restored file system
cd /
umount /mnt
17) Check the newly restored file system for consistency :
fsck /dev/rdsk/devicename
18) Create the boot blocks to restore the root file system :
installboot /usr/platform/sun4u/lib/fs/ufs/bootblk /dev/rdsk/devicename — SPARC system
installboot /usr/platform/`uname -i`/lib/fs/ufs/pboot /usr/platform/`uname -i`/lib/fs/ufs/bootblk /dev/rdsk/devicename — x86 system
19) Remove teh last backup tape, and insert a new tape onto which we can write. Make a dump level 0 backup of the newly restored system by issuing the following command :
ufsdump 0ucf /dev/rmt/n /dev/rdsk/deviceName
This step is needed because ufsrestore repositions the files and changes the inode allocations – the old backup will not truly represent the newly restored file system
20) Reboot the system :
#reboot (or)
# init 6
System gets rebooted and newly restored file systems are ready to be used.

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