Maintaining minimal free disk space Linux?

Question

linux

There is a server with a separate disk for cache. The cache size can vary by strong jumps, for example:
- 30 Gb
- 40 Gb
- 35 Gb
- 120 Gb
- 70 Gb
At the moment, the cache is cleared according to the "delete files older than X days" principle by cron.
In general, everything is fine, but the disk space is not being used optimally. On average, about 30% of the disk is used, and the rest is only at the peaks of the surges.
Tell me if there is some utility or a banal find . -delete which could delete the oldest files automatically when the disk reaches, say, 90% full. A kind of preemptive cache on the disk.
It is the storage of ordinary files that is of interest, without the use of cloud solutions, etc.

Answer 1

banal find . -delete

yes, a couple of bash and cron lines
Delete when N% full
https://stackoverflow.com/a/5912404/1603055

FILESYSTEM=/dev/sda1 # or whatever filesystem to monitor
CAPACITY=95 # delete if FS is over 95% of usage 
CACHEDIR=/home/user/lotsa_cache_files/

# Proceed if filesystem capacity is over than the value of CAPACITY (using df POSIX syntax)
# using [ instead of [[ for better error handling.
if [ $(df -P $FILESYSTEM | awk '{ gsub("%",""); capacity = $5 }; END { print capacity }') -gt $CAPACITY ]
then
    # lets do some secure removal (if $CACHEDIR is empty or is not a directory find will exit
    # with error which is quite safe for missruns.):
    find "$CACHEDIR" --maxdepth 1 --type f -exec rm -f {} \;
    # remove "maxdepth and type" if you want to do a recursive removal of files and dirs
    find "$CACHEDIR" -exec rm -f {} \;
fi

Delete the oldest files
https://superuser.com/a/1003638

DIR=/tmp
FREESPACE=1000000
find $DIR -type f | xargs ls -1rt | while read f ; do
  if [ `df --output=avail $DIR | tail -1` -ge $FREESPACE ] ; then
    break
  fi
  # rm -f $f
done

Together there somehow blind yourself already