Creating and Restore Backup Using LVM snapshot

Lvm Snapshot is ultimate way for creating a backup of that data which is already present into LVM(Logical Volume Management) devices (LV)-Logical volume.

Example: 1. We have a already created LV(logical volume) from any VG
============

of 5GiB/GB size and have copied lots of data for example 4GB

Important :
==========

When you copy or store data it stores in two maners.

i) Data blocks (original data)
ii) metadata pointers (links and location address)

@@@@@@@@@@@@@@@@@@@@ THe concept of LVM SnapShot @@@@@@@@@
————————————————————

LVM Snapshot make a link to Original LV(Logical volume)
just like soft link of a file or directory which doesn’t required much size.

So if we have 5GB of LV(logical VOlume) then we can have its metadata upto 10-15% (50MB) and We can create LVM snapshot of 50MB

—————–
Practical :24 hours
—————–

Step 1:
=======
Mount your LV (logical volume) which you have already created then fill some data.

[root@desktop69 rhel6]# mount /dev/vgcheck/lvm1 /mnt/new

step 2:
=======
copy some data here

[root@desktop69 rhel6]# touch /mnt/new/abd{1..67}
[root@desktop69 rhel6]#cp -rvf /usr/ /mnt/new

Step3 :
======

Now take a snapshot of LVM

[root@desktop69 rhel6]#lvcreate -s –size 20M –name lvmsnapshot1 /dev/vgcheck/lvm1

check by using lvs or lvdisplay command

Note: Now you can mount it to access the stored data

Article Source - http://www.rhce.co.in/creating-and-restore-backup-using-lvm-snapshot/

How to enable bash-completion in ubuntu 14.04

1. You need to reinstall bash-completion by using below command

learning@learning:~/Desktop$ sudo apt-get install –reinstall bash-completion

2. Now you need to write it in .bashrc file like below given at very last line

learning@learning:~/Desktop$ sudo vim /root/.bashrc

if [ -f /etc/bash_completion ] && ! shopt -oq posix; then

. /etc/bash_completion

fi

 

Article Source - http://www.rhce.co.in/how-to-enable-bash-completion-in-ubuntu-14-04/