can snapshot volumes used as full backup data

ramesh24 · 10-03-2009, 12:16 PM

snapshot LVM volume is only image of harddisk. can we use snapshot volume as full backup data. if our original harddisk is formated,then we can restore original state with help of snapshot volume.

acid_kewpie · 10-03-2009, 12:51 PM

No. A snapshot works by writing all changes to the disk to spare space on the disk, which is pointed to by the new copy of the inode table on the main volume. if the changes to the disk exceed the snapshot space (e.g. 20%) then the snapshot is invalid as there#s not enough space in the volume to store the differences.

naturally if you format a file system then 100% of it would change... But then if you formatted the entire harddrive, the LVM data wouldn't exist anyway, would it?

ramesh24 · 10-06-2009, 12:45 PM

Thanks for your useful information.