Backup script backs up more data than the size of the source disk?

Mark_667 · 07-16-2012, 06:22 AM

I've got a backup script that copies the entire file structure to a datestamped folder on an NFS share hosted on another machine. Oddly I've been seeing backup sizes several times the size of the source disk, does anyone have any advice on where to start troubleshooting this?

NevemTeve · 07-16-2012, 07:23 AM

Use tar+{gz/bzip2/xz}

TobiSGD · 07-16-2012, 07:44 AM

I would expect this behavior if you make extended use of hardlinks. Hardlinks can not be copied from on file-system to another, so it is every time copying the whole file again.

Chirel · 07-17-2012, 05:50 PM

Do you backup sparse files ? if so you should be aware of them, and use the options to backup them.

gnashley · 07-18-2012, 02:57 AM

Also, the block size used on the disks may be different -where block sizes are larger on the destinatin disk, then the space used will be larger.