Snap seems to have copied everything twice? Is it OK to delete one copy?

So, my computer was running low on memory (dual-booting does that, especially if your laptop didn't have that much memory to start off with), so I went looking for stuff to delete. I was surprised to find the folder /var/lib/snapd/snaps had 1.4GB of files in it, given that I really only use snap as my package manager when apt doesn't have the programs/libraries I want.

When I opened it up, this is what I found:

-rw------- 1 root root 102637568 Jan 6 16:20 core_10583.snap
-rw------- 1 root root 58052608 Oct 27 17:40 core18_1932.snap
-rw------- 1 root root 58073088 Dec 17 10:46 core18_1944.snap
-rw------- 2 root root 62349312 Dec 6 19:48 discord_119.snap
-rw------- 1 root root 62349312 Jan 3 15:32 discord_120.snap
-rw------- 1 root root 169254912 Jun 7 2020 gnome-3-28-1804_128.snap
-rw------- 1 root root 170778624 Oct 11 17:33 gnome-3-28-1804_145.snap
-rw------- 1 root root 228478976 Oct 2 01:21 gnome-3-34-1804_60.snap
-rw------- 1 root root 229629952 Jan 10 01:35 gnome-3-34-1804_66.snap
-rw------- 1 root root 67477504 Nov 25 12:31 gtk-common-themes_1513.snap
-rw------- 1 root root 67915776 Nov 28 00:34 gtk-common-themes_1514.snap
drwxr-xr-x 2 root root 4096 Apr 11 2020 partial
-rw------- 1 root root 32571392 Dec 5 18:33 snapd_10492.snap
-rw------- 1 root root 32600064 Jan 6 16:20 snapd_10707.snap
-rw------- 1 root root 53501952 Nov 25 19:32 snap-store_498.snap
-rw------- 1 root root 53522432 Dec 19 16:35 snap-store_518.snap

As you can see, there are two copies of everything - it looks like snap failed to delete the previous version while installing the new version, which probably explains why the folder ended up gobbling so much memory. I'm tempted to just delete all the old files, but I figured it was best to check this isn't just part of how snap works and those duplicate files aren't important somehow. And if this is somehow a design feature, I'd be very curious what benefits are gained by literally doubling the amount of memory that gets used up.

1 Answer

When updating, snap keeps a previous version around. So it is normal you find two instances of a specific snap.

By design, you unfortunately cannot set snap to not retain a previous version. You can retain more version if you wish by changing a refresh-retain option.

You can always remove a specific snap version with a command, but to automatically remove the backup copies of all snaps, you could use a script.