73 lines
3.2 KiB
Desktop File
73 lines
3.2 KiB
Desktop File
# This systemd unit puts the PostgreSQL storage on tmpfs and (tries to) sync
|
|
# it back at shutdown.
|
|
|
|
# Of course, in case of power failure or any problem preventing this
|
|
# unit to stop properly and sync back the data to disk : DATA LOSS.
|
|
|
|
# To install :
|
|
# - apt install rsync
|
|
# - copy this file to /etc/systemd/system/postgresqlontmpfs@.service
|
|
# - in the following lines, replace NN-xxxx by the version and cluster name targeted, for example: postgresqlontmpfs@15-main
|
|
# - systemctl enable postgresqlontmpfs@NN-xxxx
|
|
# - systemctl stop postgresql
|
|
# - systemctl start postgresqlontmpfs@NN-xxxxx
|
|
# - systemctl start postgresql
|
|
|
|
# This file is free software licensed under the WTFPL (v2)
|
|
# DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
|
|
# Version 2, December 2004
|
|
#
|
|
# Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
|
|
#
|
|
# Everyone is permitted to copy and distribute verbatim or modified
|
|
# copies of this license document, and changing it is allowed as long
|
|
# as the name is changed.
|
|
#
|
|
# DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
|
|
# TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
|
|
#
|
|
# 0. You just DO WHAT THE FUCK YOU WANT TO.
|
|
|
|
[Unit]
|
|
Description=Put /var/lib/postgresql/%I on tmpfs before PostgreSQL starts
|
|
Before=postgresql@%i.service
|
|
ConditionPathIsDirectory=/var/lib/postgresql/%I
|
|
ConditionPathExists=/usr/bin/rsync
|
|
|
|
|
|
[Install]
|
|
WantedBy=multi-user.target
|
|
|
|
|
|
[Service]
|
|
Type=oneshot
|
|
RemainAfterExit=yes
|
|
Restart=no
|
|
|
|
# We double-check that PostgreSQL is not running before doing anything
|
|
# Per https://www.freedesktop.org/software/systemd/man/systemd.service.html
|
|
# when an ExecCondition= command exits with exit code 1 through 254
|
|
# (inclusive), the remaining commands are skipped and the unit is not marked as
|
|
# failed. However, if an ExecCondition= command exits with 255 or abnormally
|
|
# (e.g. timeout, killed by a signal, etc.), the unit will be considered failed
|
|
# (and remaining commands will be skipped).
|
|
ExecCondition=/bin/sh -c "systemctl --quiet is-active postgresql@%i && echo 'PostgreSQL still active' && exit 255 || exit 0"
|
|
|
|
# If the ON-DISK directory doesn't exist, simply rename /var/lib/postgresql/NN/main to
|
|
# /var/lib/postgresql/NN/main.ON-DISK and recreate /var/lib/postgresql/NN/main
|
|
ExecStart=/bin/sh -c "if [ ! -e /var/lib/postgresql/%I.ON-DISK ] ; then mv -v /var/lib/postgresql/%I /var/lib/postgresql/%I.ON-DISK && mkdir -v /var/lib/postgresql/%I && chown -v postgres:postgres /var/lib/postgresql/%I; fi"
|
|
# Mount the tmpfs
|
|
# (note: to forcefully limit memory consumption, we can add 'size=1024M' to the mount options)
|
|
ExecStart=/bin/mount -v -t tmpfs -o uid=postgres,gid=postgres,mode=0755 none /var/lib/postgresql/%I
|
|
# Copy the ON-DISK content to the tmpfs
|
|
ExecStart=/usr/bin/rsync -avH --delete /var/lib/postgresql/%I.ON-DISK/ /var/lib/postgresql/%I/
|
|
|
|
# At stop :
|
|
# - Little notice for the logs
|
|
ExecStop=/bin/sh -c "echo 'Syncing tmpfs:/var/lib/postgresql/%i to disk'"
|
|
# - fetch back the in-memory data to disk
|
|
ExecStop=/usr/bin/rsync -avH --delete /var/lib/postgresql/%I/ /var/lib/postgresql/%I.ON-DISK/
|
|
# - destroy the tmpfs
|
|
ExecStop=/bin/umount -v /var/lib/postgresql/%I
|
|
# - put back the on-disk storage in its original path
|
|
ExecStop=/bin/sh -c "rmdir -v /var/lib/postgresql/%I && mv -v /var/lib/postgresql/%I.ON-DISK /var/lib/postgresql/%I"
|