fstrim script makes noises on some servers
we get this nightly since bungei was installed:
To: root@bungei.torproject.org
Date: Thu, 21 Mar 2019 06:25:03 +0000
/etc/cron.daily/puppet-trim-fs:
fstrim: /srv/backups/pg: the discard operation is not supported
fstrim: /srv/backups/bacula: the discard operation is not supported
this is from the following script deployed through puppet:
# by weasel
if tty > /dev/null; then
verbose="-v"
else
verbose=""
fi
awk '$9 ~ "^(ext4|xfs)$" && $4 == "/" {print $3, $5}' /proc/self/mountinfo | while read mm mountpoint; do
path="/sys/dev/block/$mm"
[ -e "$path" ] || continue
path="$(readlink -f "$path")"
while : ; do
qi="$path/queue/discard_max_bytes"
if [ -e "$qi" ]; then
[ "$(cat "$qi")" -gt "0" ] && fstrim $verbose "$mountpoint"
break
fi
# else try the parent
path="$(readlink -f "$path/..")"
# as long as it's a device
[ -e "$path/dev" ] || break
done
done
I can confirm the mapped device cannot be "trimmed":
root@bungei:/home/anarcat# fstrim -v /srv/backups/pg
fstrim: /srv/backups/pg: the discard operation is not supported
I'm unsure why that is the case. I suspect it might be a matter of adding the issue_discards
option to lvm.conf
, but I'm not sure. I also note that the discard
option is not present in crypptab
either.
In the Debian wiki SSDOptimization page, they mention a fstrim
systemd service (not required in Buster, apparently) that supposedly takes care of that work for us. It does, however, only the following command:
fstrim -av
... which doesn't seem to do anything here. It also doesn't silence the warnings from the script, so I'm not sure it's doing anything.
In any case, I welcome advice on how to deal with that one warning.