Backup fills host disk with a docker volume

[mikeymop]

Hello, I am struggling to achieve a successful initial backup to a restic repo I created on the internet.

I am using the container image with the following volume configuration:

/userdata # mounted my NAS mergerfs pool
/data     # arbitrary directory on host
/config   # arbitrary directory on host
/cache    # arbitrary directory on host
/resticTemp # $HOME/resticTemp on host

The backup starts and runs for several hours but eventually terminates with the following error:

Fatal: unable to save snapshot: Write: write /tmp/restic-temp-pack-1690927867: no space left on device

Initially I attributed this to me not ignoring the directories I mounted for cache and data so I added these ignore patterns to the backup:

/userdata/backrest/cache/**/*
/userdata/torrent/downloads/**/*

This produces the following restic command:

/bin/restic-0.16.4 backup --json /userdata -osftp.args= -oBatchMode=yes --exclude-caches --tagplan:Monthly-Backup--tagcreated-by:foo --exclude/userdata/backrest/cache/**/* --exclude/userdata/downloads/**/*--no-cache

This resulted in a full disk. I have 684gb oh data on the drive I wish to backup, and 350gb of free space on the host's disk.

I suspected this might be the tmpfs filling so I've added the following env vars to the container:

TMPDIR=/resticTemp

Which is associated with the $HOME/resticTemp:/resticTemp volume mount I've added in an attempt to mitigate this issue.

Is consuming nearly 350gb of cache in order to perform an initial backup a reasonable amount?
Am I misconfiguring backrest, or the plan, in a specific way causing the cache to balloon in size?

Any help would be appreciated.

[garethgeorge]

Hmm, off the top of my head

• TMPDIR is used for creating temporary files during upload etc iiuc.
• XDG_CACHE_HOME is another temporary location that restic uses to cache repo files w/many packs.

You might try making sure you are setting both directories. I wonder if it's actually your cache that's filling the tmpfs? This may also be a question worth asking about on the restic forums if you are actually seeing 350gb of writes.