rss.png profile for ebal on Stack Exchange, a network of free, community-driven Q&A sites
Aug
28
2012
Shrink your backup images

I am using LVM for storage to virtual machines.
One simply way to make backups (even if the machine is online) is through dd.

(but if you are using a database, online is out of question).

dd will backup the entire partition to a raw image.

Lets make an example:


# time dd if=/dev/vg01/winxp of=winxp.img bs=1024 
5242880+0 records in
5242880+0 records out
5368709120 bytes (5,4 GB) copied, 111,164 s, 48,3 MB/s

So we have a 5Gb backup raw image with sparse files into.
If only there was a way to remove sparse files to reduce the size!

Wait … it does exist: virt-sparsify


# virt-sparsify winxp.img winxp.img.spars
...
Sparsify operation completed with no errors.  Before deleting the old 
disk, carefully check that the target disk boots and works correctly.

# ls -ltr

-rw-r--r-- 1 root root 5368709120 Αύγ  28 11:55 winxp.img
-rw-r--r-- 1 root root 5368709120 Αύγ  28 11:59 winxp.img.spars

# du -h * 
5,1G    winxp.img
3,1G    winxp.img.spars

2gb sparse files have just removed !

Now you can compress the backup image to reduce the size even more:


# du -h winxp.img*

5,1G    winxp.img
3,1G    winxp.img.spars
1,4G    winxp.img.spars.lrz

We can now remove winxp.img & winxp.img.spars (8.2Gb) from our backup storage.

  1. Avatar di Nancy Nancy

    Tuesday, April 16, 2013 - 22:51:44

    Nice Tutorial i was searching about how to shrink backup to reduce the size , And i get it ,, Thanks

  2. Avatar di Backup Windows 7 Backup Windows 7

    Tuesday, April 16, 2013 - 22:52:41

    But Can You Provided More Images About It ?