Profile-sync-daemon

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profile-sync-daemon
(psd) is a tiny pseudo-daemon designed to manage browser profile(s) in tmpfs and to periodically sync back to the physical disc (HDD/SSD). This is accomplished by an innovative use of
rsync
to maintain synchronization between a tmpfs copy and media-bound backup of the browser profile(s). Additionally, psd provides several crash recovery features.
The design goals and benefits of psd are:
Transparent user experience
Reduced wear to physical drives
Speed
Since the profile(s), browser cache, etc. are relocated into
tmpfs
(RAM disk), the corresponding I/O associated with using the browser is also redirected from the physical drive to RAM, thus reducing wear to the physical drive and also greatly improving browser speed and responsiveness.
Starting with psd version 7,
fuse-overlayfs
is used to reduce the memory footprint of psd's tmpfs space and to speed up sync and unsync operations. The magic is in how the overlay mount only writes out data that has changed rather than the entire profile.
Note
Some browsers such as Chrome/Chromium or Firefox (since v21) actually keep their cache directories
separately
from their profile directory. It is not within the scope of profile-sync-daemon to modify this behavior; users are encouraged to refer to the
Chromium tweaks#Cache in tmpfs
section for Chromium and to the
Firefox on RAM
article for several workarounds.
Occasionally, updates/changes are made to the default configuration file
/usr/share/psd/psd.conf
upstream. The user copy
$XDG_CONFIG_HOME/psd/psd.conf
will need to be diffed against it. On Arch Linux, pacman should notify the user to do this.
psd can slow down
login
, as that is when it copies your browser cache to RAM.
Installation
Install
the
profile-sync-daemon
package.
Configuration
When you run psd for the first time, it will create
$XDG_CONFIG_HOME/psd/psd.conf
(referred to hereafter as the configuration file) which contains all settings. You can run the
psd
command before using
psd.service
to create this file without starting synchronization.
Note
Any edits made to this file while psd is active will be applied only after
psd.service
has been
restarted
.
Optionally define which browsers are to be managed in the
BROWSERS
array. If none are defined, the default is all detected browsers.
Optionally disable the use of crash-recovery snapshots (not recommended). Do this in the
USE_BACKUPS
variable.
Optionally define the number of crash-recovery snapshots to keep. Do this in the
BACKUP_LIMIT
variable.
Example: Let us say that Chromium, Opera and Firefox are installed but only Chromium and Opera are to be sync'ed to tmpfs since the user keeps Firefox as a backup browser and it is seldom used:
BROWSERS=(chromium opera)
Beginning with version 7 of psd, support for
fuse-overlayfs
is required. This feature requires at least a Linux kernel version of 4.18 or greater.
Supported browsers
Currently, the following browsers are auto-detected and managed:
Chromium
conkeror-git
AUR
Epiphany
falkon
Firefox
(all flavors including stable, beta, and nightly)
google-chrome
AUR
google-chrome-beta
AUR
google-chrome-dev
AUR
icecat
AUR
Luakit
Opera
Otter Browser
palemoon
AUR
Qutebrowser
seamonkey
AUR
surf
AUR
vivaldi
zen-browser
AUR
Usage
Start/enable
the
psd.service
user unit
. Additionally, a provided resync-timer will run an hourly resync from tmpfs back to the disk. The resync-timer is started automatically with
psd.service
so there is no need to manually start the timer.
Preview (parse) mode
Run
psd parse
to view what psd will do/is doing based on
$XDG_CONFIG_HOME/psd/psd.conf
. It will also provide useful information such as profile size, paths, and if any recovery snapshots have been created.
Tips and tricks
Sync at more frequent intervals
The package provided re-sync timer triggers once per hour. Users may optionally redefine this behavior simply by
extending the systemd unit
. The example below changes the timer to sync once every ten minutes (note that
OnUnitActiveSec
needs to be cleared before being re-assigned
[1]
):
~/.config/systemd/user/psd-resync.timer.d/frequency.conf
[Unit]
Description=Timer for Profile-sync-daemon - 10min

[Timer]
OnUnitActiveSec=
OnUnitActiveSec=10min
See
systemd.timer(5)
for additional options.
Allocate more memory to accommodate profiles in /run/user/xxxx
The standard way of controlling the size of
/run/user
is the RuntimeDirectorySize directive in
/etc/systemd/logind.conf
(see
logind.conf(5)
for more). By default, 10% of physical memory is used but one can increase it safely. Remember that tmpfs only consumes what is actually used; the number specified here is just a maximum allowed.
Snapshots
Odds are the "last good" backup of your browser profiles is just fine still sitting happily on your filesystem. Upon restarting psd (on a reboot for example), a check is performed to see if the symlink to the tmpfs copy of your profile is valid. If it is invalid, psd will snapshot the "last good" backup before it rotates it back into place. This is more for a sanity check that psd did no harm and that any data loss was a function of something else.
Note
Users can disable the snapshot/backup feature entirely by uncommenting and setting the
USE_BACKUPS
variable to
"no"
in
$XDG_CONFIG_HOME/psd/psd.conf
if desired.
You will find the snapshot in the same directory as the browser profile and it will contain a date-time-stamp that corresponds to the time at which the recovery took place. For example, chromium will be
~/.config/chromium-backup-crashrecovery-20130912_153310
-- of course, the date_time suffix will be different for you.
To restore your snapshots:
Stop
the
psd.service
user unit
.
Confirm that there is no symlink to the tmpfs browser profile directory. If there is, psd did not stop correctly for other reasons.
Move the "bad" copy of the profile to a backup (do not blindly delete anything).
Copy the snapshot directory to the name that browser expects.
Example using Chromium:
$ mv ~/.config/chromium ~/.config/chromium-bad
$ cp -a ~/.config/chromium-backup-crashrecovery-20130912_153310 ~/.config/chromium
At this point you can launch chromium which will use the backup snapshot you just copied into place. If all is well, close the browser and restart psd. You may safely delete
~/.config/chromium-backup-crashrecovery-20130912_153310
at this point.
Clean all the snapshot with the clean mode
Running
psd clean
will delete ALL recovery snapshots that have accumulated. Run this only if you are sure that you want to delete them.
Support
Post in the
discussion thread
with comments or concerns.
See also
Web Upd8 - Keep Your Browser Profiles In tmpfs (RAM) For Reduced Disk Writes And Increased Performance With Profile Sync Daemon
Nicolas Bernaerts - Tweaks for SSD drive