This is a bit of a head scratcher Have a freshly migrated Discourse instance on a new server. Getting the error in logs: PG::DiskFull (ERROR: could not resize shared memory segment "/PostgreSQL.1759815625" to 8388608 bytes: No space left on device ) Itâ€™s strange because, the previous server (64gb ram) didnâ€™t have this issue and I had these set: db_shared_buffers: "25632MB" db_work_mem: "160MB" On the new server (128gb ram), I canâ€™t increase above the baseline defaults (I tried tripling the values below and get the same PG DiskFull error): db_shared_buffers: "128MB" db_work_mem: "40MB" Previous machine has docker 27.x on it (auto installed via the discourse installer). New machine installed docker.io as per instructions (so 26.x). I tried switching to docker 27.x to see if that was related - but it didnâ€™t change anything. Both are on the Stable Discourse branch, version 3.3.2. It seems shm_size might be the main culprit: PG throws could not resize shared memory segment error Installation This is due to the fact that docker by default restricts shared memory size to 64MB which makes pg10 run afoul of this limitation when doing a number of scatter/gather jobs in parallel: Outside the container: supermathie@host: ~ $ df -h /dev/shm Filesystem Size Used Avail Use% Mounted on none 63G 1.2M 63G 1% /run/shm Inside the container: supermathie@host: ~ $ docker exec -it postgres-master df -h /dev/shm Filesystem Size Used Avail Use% Mounted on shm â€¦ Though no idea why it wasnâ€™t an issue on the previous server and it is on the new server. The only other main difference is the old server uses Ubuntu 22.04 LTS and the new server is on 24.04 LTS. I tried this also, but the changes get overwritten when the container is started again Docker shm_size Option in app.yml Feature Hey @Ghan In the meantime (for testing purposes, see caveat below), you can change this directly with docker after the container is built, as follows: Edit the /var/lib/docker/containers/$CONTAINER_ID/hostconfig.json file directly. For example, change the value for ShmSize in the file above. Stop and restart the container. In our docker container hostconfig file, it looks like this: "ShmSize":536870912, [Screen Shot 2020-12-29 at 12.39.17 PM] HTH Caveat: Some people have posted that yâ€¦ shm_size appears to be hardcoded into the launcher: github.com discourse/discourse_docker/blob/40169e87630008d00dcc559606eecebca2d82e78/launcher#L600 if [ -z "$SKIP_MAC_ADDRESS" ] ; then mac_address="--mac-address $($docker_path run $user_args -i --rm -a stdout -a stderr $image /bin/sh -c "echo $hostname | md5sum | sed 's/^$..$$..$$..$$..$$..$.*$/02:\1:\2:\3:\4:\5/'")" fi if [ ! -z "$START_CMD_ONLY" ] ; then docker_path="true" fi set -x $docker_path run --shm-size=512m $links $attach_on_run $restart_policy "${env[@]}" "${labels[@]}" -h "$hostname" \ -e DOCKER_HOST_IP="$docker_ip" --name $config -t "${ports[@]}" $volumes $mac_address $user_args \ $run_image $boot_command ) exit 0 } run_run() { set_template_info github.com discourse/discourse_docker/blob/40169e87630008d00dcc559606eecebca2d82e78/launcher#L616 } run_run() { set_template_info set_volumes set_links set_run_image unset ERR (exec $docker_path run --rm --shm-size=512m $user_args $links "${env[@]}" -e DOCKER_HOST_IP="$docker_ip" -i -a stdin -a stdout -a stderr $volumes $run_image \ /bin/bash -c "$run_command") || ERR=$? if [[ $ERR > 0 ]]; then exit 1 fi } run_bootstrap() { # Is the image available? # If not, pull it here so the user is aware what's happening. github.com discourse/discourse_docker/blob/40169e87630008d00dcc559606eecebca2d82e78/launcher#L659 fi run_command="$run_command /pups/bin/pups --stdin" echo $run_command unset ERR tmp_input_file=$(mktemp) echo "$input" > "$tmp_input_file" (exec cat "$tmp_input_file" | $docker_path run --shm-size=512m $user_args $links "${env[@]}" -e DOCKER_HOST_IP="$docker_ip" --cidfile $cidbootstrap -i -a stdin -a stdout -a stderr $volumes $image \ /bin/bash -c "$run_command") || ERR=$? rm -f "$tmp_input_file" unset FAILED # magic exit code that indicates a retry if [[ "$ERR" == 77 ]]; then $docker_path rm `cat $cidbootstrap` rm $cidbootstrap exit 77 Any insights or help would be appreciated! 1 post - 1 participant Read full topic

Posted by User Bot

30 Nov, 2024

Updated at 14 Dec, 2024

Can't increase db_shared_buffers (0.1% of total ram) and db_work_mem (0.03% of total ram)

This is a bit of a head scratcher

Have a freshly migrated Discourse instance on a new server.

Getting the error in logs: PG::DiskFull (ERROR: could not resize shared memory segment "/PostgreSQL.1759815625" to 8388608 bytes: No space left on device )

Itâ€™s strange because, the previous server (64gb ram) didnâ€™t have this issue and I had these set:

db_shared_buffers: "25632MB"
db_work_mem: "160MB"

On the new server (128gb ram), I canâ€™t increase above the baseline defaults (I tried tripling the values below and get the same PG DiskFull error):

db_shared_buffers: "128MB"
db_work_mem: "40MB"

Previous machine has docker 27.x on it (auto installed via the discourse installer). New machine installed docker.io as per instructions (so 26.x). I tried switching to docker 27.x to see if that was related - but it didnâ€™t change anything. Both are on the Stable Discourse branch, version 3.3.2.

It seems shm_size might be the main culprit:

Though no idea why it wasnâ€™t an issue on the previous server and it is on the new server. The only other main difference is the old server uses Ubuntu 22.04 LTS and the new server is on 24.04 LTS.

I tried this also, but the changes get overwritten when the container is started again

shm_size appears to be hardcoded into the launcher:

github.com

discourse/discourse_docker/blob/40169e87630008d00dcc559606eecebca2d82e78/launcher#L600


      
               if [ -z "$SKIP_MAC_ADDRESS" ] ; then
                mac_address="--mac-address $($docker_path run $user_args -i --rm -a stdout -a stderr $image /bin/sh -c "echo $hostname | md5sum | sed 's/^\(..\)\(..\)\(..\)\(..\)\(..\).*$/02:\1:\2:\3:\4:\5/'")"
               fi
          
               if [ ! -z "$START_CMD_ONLY" ] ; then
                 docker_path="true"
               fi
          
               set -x
          
               $docker_path run --shm-size=512m $links $attach_on_run $restart_policy "${env[@]}" "${labels[@]}" -h "$hostname" \
                  -e DOCKER_HOST_IP="$docker_ip" --name $config -t "${ports[@]}" $volumes $mac_address $user_args \
                  $run_image $boot_command
          
             )
             exit 0
          
          }
          
          run_run() {
            set_template_info

github.com

discourse/discourse_docker/blob/40169e87630008d00dcc559606eecebca2d82e78/launcher#L616


      
          
          }
          
          run_run() {
            set_template_info
            set_volumes
            set_links
            set_run_image
          
            unset ERR
            (exec $docker_path run --rm --shm-size=512m $user_args $links "${env[@]}" -e DOCKER_HOST_IP="$docker_ip" -i -a stdin -a stdout -a stderr $volumes $run_image \
              /bin/bash -c "$run_command") || ERR=$?
          
            if [[ $ERR > 0 ]]; then
              exit 1
            fi
          }
          
          run_bootstrap() {
            # Is the image available?
            # If not, pull it here so the user is aware what's happening.

github.com

discourse/discourse_docker/blob/40169e87630008d00dcc559606eecebca2d82e78/launcher#L659


      
          fi
          run_command="$run_command /pups/bin/pups --stdin"
          
          echo $run_command
          
          unset ERR
          
          tmp_input_file=$(mktemp)
          
          echo "$input" > "$tmp_input_file"
          (exec cat "$tmp_input_file" | $docker_path run --shm-size=512m $user_args $links "${env[@]}" -e DOCKER_HOST_IP="$docker_ip" --cidfile $cidbootstrap -i -a stdin -a stdout -a stderr $volumes $image \
            /bin/bash -c "$run_command") || ERR=$?
          
          rm -f "$tmp_input_file"
          
          unset FAILED
          # magic exit code that indicates a retry
          if [[ "$ERR" == 77 ]]; then
            $docker_path rm `cat $cidbootstrap`
            rm $cidbootstrap
            exit 77

Any insights or help would be appreciated!

1 post - 1 participant

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Can't increase db_shared_buffers (0.1% of total ram) and db_work_mem (0.03% of total ram)