Back up of a File System in mounted state: snapshot

Back up of a File System in mounted state:

task:

-if suppose my boss said, it should be mounted only  /jumbo and i want back up & don't want any updates.

ans: fssnap                    // snap shot

- user can't accessible until snap shot.

Back up of a File System in mounted state:

- To take a backup of a File System in mounted state the option used is 'snap shot'

- while taking a 'snap shot' all the users will face a 'pause mode'. i.e they can view the File System, but they can't update the data to the File System.

- To create a File System, Format it, mount it & write the data into the mount point.

# Format                // take slice s6, 100m size

# newfs /dev/rdsk/c0t0d0s6

# mkdir /joy

# mount /dev/dsk/c0t0d0s6 /joy

# cd /joy

# touch j1 j2 j3 j4 j5

# ls

# df -h

  s6   (mounted state)

To create a snap shot:

# fssnap -F ufs -o bs=/var/tmp  /joy           // F- file

/dev/fssnap/0 : snap shot is a image of slice only ( it's not a backup, it is only a image, whatever file in s6 that will be in snap shot)

to verify a snapshot:

# mkdir /toy

# mount -F ufs -o -ro /dev/fssnap/0 /toy

# df -h

/s6   -   /joy

/dev/fssnap/0  -  /toy

# cd /joy

# ls

# cd /toy

# ls

//both have same data in joy & toy, so successfully taken of snap shot

to take a backup of a snapshot:

#  umount /toy

backup:

# ufsdump 0uf /dev/rmt/0 /dev/fssnap/0

till now 3 copies done

1. s6

2. /dev/fssnap/0

3. /dev/rmt/0

verify:

# cat /etc/dumpdates

to verify the backup & recover:

# fssnap -i

0  /joy

to date the snapshot:

# fssnap -d /joy

// deleted snapshot 0

# fssnap -i

//no snap shots

# umount /joy

# newfs /dev/rdsk/c0t0d0s6

// data lost

# mount /dev/dsk/c0t0d0s6 /joy

# cd /joy

# ls

// nothing, bcoz its formated

to recover the data:

# ufsrestore rvf /dev/rmt/0

check:

# df -h

# cd /joy

# ls

(yes, all recovered)

Note: when we recover the data by using 'ufsrestore' bydefault we are setting one directory