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

Important :
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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 @@@@@@@@@
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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

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Practical :24 hours
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Step 1:
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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:
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copy some data here

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

Step3 :
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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/