I recently switched from EXT4 to BTRFS and my subjective impression is a dramatic improvement in Qubes OS performance. However I am not 100% sure which of the following three factors is to credit or if it is a combination of all of these:
- it’s a new install with restored backup (not much fragmentation, snapshots etc. yet)
- I also exchanged the SSD from a QVO to a PRO (should explain some of the improvement)
- switch to BTRFS
There is an overall performance improvement, which I am ready to explain with 1) and 2), but there is a dramatic improvement when shutting down a large (100 GB) HVM and when starting a Qubes Backup from a 30+ seconds delay to literally nothing.
I am wondering if there are some folks around here, who know more about BTRFS and can explain a bit why it would improve these situations. My guess is that it has something to do with snapshots, lazy writes, etc. But I would love to hear from an expert.