I'm using rsnapshot to back up the computers on my home network. For years, I've been using Ext4-on-LUKS on USB hard disks and getting good results. Recently I added a Btrfs-on-LUKS disk to get the benefit of data checksumming, but performance is abysmal: where I can back up to Ext4-on-LUKS in a consistent 45 minutes, the time needed to back up to Btrfs-on-LUKS is seven hours and increasing as the disk fills up.
The limiting factor appears to be disk I/O: my monitoring software shows a load average between 3 and 5, but
top shows the CPU is 95% either "idle" or "waiting".
Is there anything I can tweak to speed things up?
Asked by Mark
(4665 rep)
Jun 14, 2023, 05:56 PM