Dear Snap Team,
Can you please share the link to snapd disk usage optimisations/internals?
Problem 1: Users laptop (my) allocates noticeable amount for snap files (without ability to clean?).
Problem 2: Canonical self-hosted runners reserves noticeable amount of free space for snaps cache/seeds.
Problem 1 details. The findings on my laptop:
> du -sh /var/lib/snapd/snaps /var/lib/snapd/seed/snaps/
13G /var/lib/snapd/snaps
2.7G /var/lib/snapd/cache/
834M /var/lib/snapd/seed/snaps/
Note: firefox_*.snap exist 11 times!
10:36:33 âś” taurus:~$ ls -lah /var/lib/snapd/snaps/firefox*
-rw------- 1 root root 255598592 May 15 02:12 firefox_2666.snap
-rw------- 1 root root 256364544 May 22 01:41 firefox_2696.snap
-rw------- 1 root root 255090688 May 25 08:01 firefox_2713.snap
-rw------- 1 root root 252964864 Jul 5 16:59 firefox_2865.snap
-rw------- 1 root root 248451072 Jul 18 20:52 firefox_2934.snap
-rw------- 1 root root 249819136 Aug 3 08:55 firefox_2967.snap
-rw------- 2 root root 248729600 Aug 14 11:26 firefox_2987.snap
-rw------- 2 root root 249700352 Aug 10 10:16 firefox_3001.snap
-rw------- 1 root root 249679872 Aug 14 09:00 firefox_3016.snap
-rw------- 1 root root 249290752 Aug 17 09:04 firefox_3027.snap
-rw------- 1 root root 249290752 Aug 21 20:54 firefox_3039.snap
I cannot find any snap clean (like an apt clean) to force local cleanup (if I urgently need 15G locally).
Proposal 1: add snap clean to remove *.snap files from mentioned above folders, to mimic common apt clean logic. Also consider to execute it periodically to keep 1-2 the latest snap revisions only.
Problem 2: the similar issue we have on Canonical self-hosted runners which we are using for CI/CD in Juju charms.
Each Juju VM requires 2Gb of disk space (partially because we store snap cache+seeds on each Juju VM, including Juju controller). See the initial thread here.
The list of cached snap artifacts after the test: https://pastebin.canonical.com/p/GfNRHs2XPZ/ , please notice there the same snaps on the server and inside each LXD container.
Proposal 2: allow refresh.retain=0 (to be set for CI/CD containers, etc):
> sudo snap set system refresh.retain=0
error: cannot perform the following tasks:
- Run configure hook of "core" snap (run hook "configure": retain must be a number between 2 and 20, not "0")
P.S. on the same server, snaps inside cache and inside seeds are linked to the same inode, but it doesn’t help for containers and doesn’t work in a real life (seeded 1969, but cached 2666+):
11:14:52 âś” taurus:~$ ls -lah /var/lib/snapd/snaps/firefox*
-rw------- 1 root root 244M May 15 02:12 /var/lib/snapd/snaps/firefox_2666.snap
-rw------- 1 root root 245M May 22 01:41 /var/lib/snapd/snaps/firefox_2696.snap
-rw------- 1 root root 244M May 25 08:01 /var/lib/snapd/snaps/firefox_2713.snap
-rw------- 1 root root 242M Jul 5 16:59 /var/lib/snapd/snaps/firefox_2865.snap
-rw------- 1 root root 237M Jul 18 20:52 /var/lib/snapd/snaps/firefox_2934.snap
-rw------- 1 root root 239M Aug 3 08:55 /var/lib/snapd/snaps/firefox_2967.snap
-rw------- 2 root root 239M Aug 10 10:16 /var/lib/snapd/snaps/firefox_3001.snap
-rw------- 1 root root 193M Aug 13 13:48 /var/lib/snapd/snaps/firefox_3005.snap
-rw------- 1 root root 239M Aug 14 09:00 /var/lib/snapd/snaps/firefox_3016.snap
11:14:55 âś” taurus:~$ ls -lah /var/lib/snapd/seed/snaps/firefox*
-rw------- 1 root root 239M Oct 20 2022 /var/lib/snapd/seed/snaps/firefox_1969.snap
Question 3: Why do we seed revision 1969 if channel deploys 2987?
> cat /var/lib/snapd/seed/seed.yaml
snaps:
-
name: firefox
channel: stable/ubuntu-22.10
file: firefox_1969.snap
...
> snap switch firefox --channel stable/ubuntu-22.10
"firefox" switched to the "latest/stable/ubuntu-22.10" channel
> sudo snap refresh firefox
Download snap "firefox" (2987) from channel "latest/stable/ubuntu-22.10"
Thank you!