Why is `private.img` kept around for volumes with `revisions_to_keep = 0`?

[rustybird]

@qpost135

How could the kernel version have been the root cause, when he switched from a working non-BTRFS 4.2 to a broken BTRFS 4.2 and then back to a working non-BTRFS 4.2?

Since Btrfs and LVM exercise very different code paths in the kernel (with that presumably resulting in equally different patterns of communication with the SSD), I wouldn’t be surprised if a kernel change affected one and not the other. That doesn’t even mean that the kernel should necessarily take the blame - or not as the root cause anyway: Drive firmware can be… quirky.

But this is just speculation.

@qpost135

I’m also planning to do a reinstall with default settings within the next days.

Any settings I should/could check before doing this?

Yes:

@rustybird

Fragmentation? It can be checked with

sudo filefrag /var/lib/qubes/appvms/data/private.img