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Partition /mnt/wsl/docker-desktop-data/isocache filling up to 100%

Hi All, today has been my second time to encounter a strange thing:

My containers couldn’t startup or show the error message ‘no space on device left’ during startup after my Windows 10 had done an Update and Restart by itself in the night and i had to startup my whole system again (development sytem for multiple Websites on my working computer).

After some intense research i could pinpoint the problem down to the isocache mount from the “docker desktop for windows”, which is at 100% usage. Last time i could overcome it so far by increasing the max. size of the vhdx for this mount ( C:\Users******\AppData\Local\Docker\wsl\data\ext4.vhdx ) from 200GB to 500GB - but that can’t be the real solution.
I already tried to optimize it (after shutting down docker and WSL) with the command “Optimize-VHD -mode full ext4.vhdx” - but no change.

root@*******:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sdb 251G 197G 42G 83% /
tmpfs 13G 252M 13G 2% /mnt/wsl
tools 1.9T 873G 989G 47% /init
none 13G 0 13G 0% /dev
none 13G 8.0K 13G 1% /run
none 13G 0 13G 0% /run/lock
none 13G 0 13G 0% /run/shm
none 13G 0 13G 0% /run/user
tmpfs 13G 0 13G 0% /sys/fs/cgroup
C:\ 1.9T 873G 989G 47% /mnt/c
D:\ 100M 33M 68M 33% /mnt/d
M:\ 451G 315G 137G 70% /mnt/m
N:\ 16G 7.6G 7.8G 50% /mnt/n
/dev/sdd 480G 464G 0 100% /mnt/wsl/docker-desktop-data/isocache
none 13G 12K 13G 1% /mnt/wsl/docker-desktop/shared-sockets/host-services
/dev/sdc 251G 119M 239G 1% /mnt/wsl/docker-desktop/docker-desktop-proxy
/dev/loop0 369M 369M 0 100% /mnt/wsl/docker-desktop/cli-tools
tmpfs 13G 412K 13G 1% /mnt/wsl/docker-desktop-data/tarcache/entries/docker.tar/362570e871de9b43d12fa4022ac7e29989099f93ed53945fbf060222d501e6e9/containers/services/docker/tmp
overlay 13G 412K 13G 1% /mnt/wsl/docker-desktop-data/tarcache/entries/docker.tar/362570e871de9b43d12fa4022ac7e29989099f93ed53945fbf060222d501e6e9/containers/services/docker/rootfs

But the content of that mount is just 3GB?!?!?

root@*******:~# du -sh /mnt/wsl/docker-desktop-data/isocache
3.0G /mnt/wsl/docker-desktop-data/isocache

My system info:

Windows 10 Professionell 64-bit
Version 2004 (Build 19041.685)
Intel i7-7700

Docker Desktop community
Version (49550)
Engine: 19.03.13
Compose: 1.27.4
Kubernetes: v1.19.3
Notary: 0.6.1
Credential Helper: 0.6.3
Snyk: v1.424.4

Use the WSL2 based engine

Using WSL2-Linux-Distribution “Ubuntu 20.04”

Same here, solved with:
docker builder prune

which removes the build cache.

That command didn’t change anything on my system, still 100% usage. I had “reinstalled” my docker for windows by deleting the “ext4.vhdx” file and could work again - just lost all my container - but yesterday it happened again, during developing one of my web applications (not building any image)?!?!?!?!?!?