I’m using Urbackup Server 2.033 on a Debian Jessie Host using BTRFS as storage filesystem.
So one of my clients is a database server, which I backup incrementally once every hour. Just the MyISAM table files.
If I look at the statistics of the urbackup webui, it says that the total usage of files is 2.3TB
Now I’m guessing it’s not taking into account things like compression and deduplication when counting the statistics. Since if I look at the available space of the server directly via command line, both with “df -h” and “btrfs fi df /storage”
It shows me that only about 850G of Space are currently used.
Ok, so far so good.
The part that worries me slightly, is how Urbackup determines how much free space there is left.
Specifically considering soft quotas and Urbackup’s decision process about when to delete old full or incremental backups to free up space.
Yes, on btrfs it is more of a upper bound on the storage usage.
There is currently no way to figure out the actual storage usage on btrfs.
There is a way to find out the compressed size of a file but it is horribly slow
If btrfs quotas are enabled it shows the uniquely used storage space per group and total storage usage, but there is no way to find out with which other clients the space is shared
Enabling btrfs quota’s breaks btrfs so you should not do that currently anyway
The global soft quota is enforced based on the output of df. The client specific quota uses the internal storage usage (see manual for details).
The other question is what most people want to have per client/group. If you have 100GB of Dropbox storage this is before compression and deduplication.
ok, so if I have 3TB of space. And my df -h output shows that only 850G of space is acuatually used, then I don’t have to worry about urbackup deleting backups because of space? Even if the statistics would show 3TB of file usage?