# osync [](https://travis-ci.org/deajan/osync) [](https://opensource.org/licenses/BSD-3-Clause) [](https://github.com/deajan/osync/releases/latest) [](http://isitmaintained.com/project/deajan/osync "Percentage of issues still open")
osync is a stateful synchronizer. This means it's agentless and doesn't have to monitor files for changes. Instead, it compares replica file lists between two runs.
A full run takes about 2 seconds on a local-local replication and about 7 seconds on a local-remote replication.
osync uses a initiator / target sync schema. It can sync local to local or local to remote directories. By definition, initiator replica is always a local directory on the system osync runs on.
osync uses pidlocks to prevent multiple concurrent sync processes on/to the same initiator / target replica.
Currently, it has been tested on CentOS 5.x, 6.x, 7.x, Fedora 22-25, Debian 6-8, Linux Mint 14-18, Ubuntu 12.04-12.10, FreeBSD 8.3-11, Mac OS X and pfSense 2.3.x.
In order to run osync the quickest (without transferring file attributes, without softdeletion, without prior space checks and without remote connectivity checks, you may use the following:
No-Maxtime option will disable execution time checks, which is usefull for big initial sync tasks that might take long time. Next runs should then only propagate changes and take much less time.
Once you're confident about your first runs, you may add osync as a cron task like the following in /etc/crontab which would run osync every 30 minutes:
Please note that this syntax works for RedHat / CentOS. On Debian you might want to remove the username (ie root) in order to make the crontab entry work.
You may want to sequentially run multiple sync sets between the same servers. In that case, osync-batch.sh is a nice tool that will run every osync conf file, and, if a task fails,
run it again if there's still some time left.
The following example will run all .conf files found in /etc/osync, and retry 3 times every configuration that fails, if the whole sequential run took less than 2 hours.
This can be a drawback on functionnality versus scheduled mode because this mode only launches a sync task if there are file modifications on the initiator replica, without being able to monitor the target replica.
Target replica changes are only synced when initiator replica changes occur, or when a given amount of time (default 600 seconds) passed without any changes on initiator replica.
Osync file monitor mode may be run as system service with the osync-srv script.
You may run the install.sh script which should work in most cases or copy the files by hand (osync.sh to /usr/bin/local, sync.conf to /etc/osync, osync-srv to /etc/init.d for initV, osync-srv@.service to /usr/lib/systemd/system for systemd, osync-srv-openrc to /etc/init.d/osync-srv-openrc for OpenRC).
InitV specific instructions:
Any configuration file found in /etc/osync will create a osync daemon instance when service is launched on initV with:
When submitting a PR, please be sure to modify files in dev directory (dev/n_osync.sh, dev/ofunctions.sh, dev/common_install.sh etc) as most of the main files are generated via merge.sh.
When testing your contribs, generate files via merge.sh or use bootstrap.sh which generates a temporary version of n_osync.sh with all includes.
Unit tests are run by travis on every PR, but you may also run them manually which adds some tests that travis can't do, via dev/tests/run_tests.sh
SSH port can be changed on the fly via environment variable SSH_PORT, eg: SSH_PORT=2222 dev/tests/run_tests.sh
