bug#39774: guix incorrectly says "No space left on device"

[Jesse Gibbons <jgibbons2357@gmail.com>]

On Mon, 2020-02-24 at 22:15 -0500, Julien Lepiller wrote:
> Le 24 février 2020 22:01:45 GMT-05:00, Jesse Gibbons <
> jgibbons2357@gmail.com> a écrit :
> > I have a laptop with two drives. A few days ago, when I ran `df -h`
> > it
> > outputs:
> > Filesystem      Size  Used Avail Use% Mounted on
> > none             16G     0   16G   0% /dev
> > /dev/sdb1       229G  189G   29G  87% /
> > /dev/sda1       458G  136G  299G  32% /gnu/store
> > tmpfs            16G     0   16G   0% /dev/shm
> > none             16G   64K   16G   1% /run/systemd
> > none             16G     0   16G   0% /run/user
> > cgroup           16G     0   16G   0% /sys/fs/cgroup
> > tmpfs           3.2G   16K  3.2G   1% /run/user/983
> > tmpfs           3.2G   60K  3.2G   1% /run/user/1001
> > 
> > As you can see, /dev/sda1 is the drive mounted on /gnu/store.
> > Everything in the store is written to it, and it has plenty of
> > space
> > available.
> > 
> > Guix sometimes says there is "No space left on device". This always
> > happens in particular when I try `guix gc --optimize`, but it
> > sometimes
> > happens when I call `guix pull` or `guix upgrade`. When guix pull
> > or
> > guix upgrade fails with this message, I can clear up more space by
> > deleting ~/.cache and emtpying my trash and it works.
> > 
> > 
> > Today I have also seen this happen when I'm trying to upgrade a
> > large
> > profile. It said it could not build anything because there was no
> > more
> > disk space, even after I cleaned up /dev/sdb1 to 40% use. It
> > finally
> > recognized the empty disk space when I called guix gc and it
> > deleted a
> > few of the dependencies needed for the upgrades. But it didn't take
> > long to trigger this bug again. Here's the new output of `df -h`:
> > 
> > Filesystem      Size  Used Avail Use% Mounted on
> > none             16G     0   16G   0% /dev
> > /dev/sdb1       229G   86G  131G  40% /
> > /dev/sda1       458G  182G  253G  42% /gnu/store
> > tmpfs            16G     0   16G   0% /dev/shm
> > none             16G   80K   16G   1% /run/systemd
> > none             16G     0   16G   0% /run/user
> > cgroup           16G     0   16G   0% /sys/fs/cgroup
> > tmpfs           3.2G   24K  3.2G   1% /run/user/983
> > tmpfs           3.2G   12K  3.2G   1% /run/user/1000
> > tmpfs           3.2G   60K  3.2G   1% /run/user/1001
> > 
> > Any clues why this happens and what can be done to fix it? Could it
> > be
> > related to how /dev/sdb1 is 229G large, and the total used space in
> > /
> > and /gnu/store is more than that?
> > 
> > -Jesse
> 
> There could be two explanations: you've run out of inodes or the
> filesystem that was out of space is not the one you think (maybe it
> was during a build and your /tmp is a tmpfs?). Try `df -i`.
~$ df -ih
Filesystem     Inodes IUsed IFree IUse% Mounted on
none             4.0M   525  4.0M    1% /dev
/dev/sdb1         15M   77K   15M    1% /
/dev/sda1         30M   29M 1015K   97% /gnu/store
tmpfs            4.0M     1  4.0M    1% /dev/shm
none             4.0M    47  4.0M    1% /run/systemd
none             4.0M     4  4.0M    1% /run/user
cgroup           4.0M    11  4.0M    1% /sys/fs/cgroup
tmpfs            4.0M    13  4.0M    1% /run/user/983
tmpfs            4.0M    24  4.0M    1% /run/user/1001
tmpfs            4.0M     1  4.0M    1% /run/user/1000

That makes sense now. /dev/sda1 (mounted on /gnu/store) was out of
inodes. Is there a way to increase the maximum number of inodes a
partition can use? Or perhaps divide the store among multiple
partitions?