qubist
February 19, 2026, 2:36pm
1
Hi,
I am observing something I can’t explain:
On debian-13-xfce:
# fstrim -v /
/: 13.7 GiB (14715064320 bytes) trimmed
# lsblk --discard
NAME DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
xvda 0 512K 2T 0
├─xvda1 0 512K 2T 0
├─xvda2 0 512K 2T 0
└─xvda3 0 512K 2T 0
xvdb 0 512K 2T 0
xvdc 0 512K 2T 0
├─xvdc1 0 512K 2T 0
└─xvdc3 0 512K 2T 0
xvdd 0 0B 0B 0
On debian-13-minimal:
# fstrim -v /
fstrim: /: the discard operation is not supported
# lsblk --discard
NAME DISC-ALN DISC-GRAN DISC-MAX DISC-ZERO
xvda 0 0B 0B 0
├─xvda1 0 0B 0B 0
├─xvda2 0 0B 0B 0
└─xvda3 0 0B 0B 0
xvdb 0 0B 0B 0
xvdc 0 0B 0B 0
├─xvdc1 0 0B 0B 0
└─xvdc3 0 0B 0B 0
xvdd 0 0B 0B 0
What is the reason for this discrepancy?
1 Like
ephile
February 19, 2026, 2:42pm
2
fstrim -av works for me in the minimal template.
1 Like
Is the ‘root’ volume of debian-13-minimal stored on a different pool that’s using the legacy ‘file’ driver?
Is Bleachbit free space cleaner an alternative to insecure disk wipe?
qubist
February 19, 2026, 3:03pm
5
@rustybird
Is the ‘root’ volume of debian-13-minimal stored on a different pool that’s using the legacy ‘file’ driver?
Yes.
Just one of the many problems with the legacy ‘file’ driver. In this case, it’s because its device-mapper based snapshot implementation in dom0 does not support discard on the kernel level.
opened 02:15AM - 12 Feb 21 UTC
C: core
release notes
P: default
C: storage
**Qubes OS version (if applicable)**
R4.1
**Affected component(s) or fun… ctionality (if applicable)**
core
**Brief summary**
1. Add some verbose notification about using deprecated storage driver in R4.1. I think this can be a notification at the system startup (can be added to the code of one of the widgets, for example qui-updates one). Also, add a warning when creating new "file" pool. Maybe also when listing storage pools?
2. Do not create "file" pool automatically during system installation. But do create file-reflink for `/var/lib/qubes` directory, for compatible filesystems.
3. Document migration off the file driver (either to file-reflink or to lvm), and link to it from release notes and the notification. In-place migration is preferred if possible, otherwise document reinstall method.
**Additional context**
The file storage driver is very inefficient and also some features are impossible to achieve using its old architecture (it simulates CoW volumes using dm-snapshot, which limits snapshots levels to 1). Example issues caused by its inferior features:
- #4324
- #6329
- #3255
5 Likes
qubist
February 19, 2026, 3:52pm
7
@rustybird
You are a living encyclopedia of file/snapshot/volume management stuff.
3 Likes
