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#LyX 2.1 created this file. For more info see http://www.lyx.org/
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\pdf_title "Osync Configuration guide"
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\begin_body
\begin_layout Title
Osync v0.99 RC4 Documentation
\end_layout
\begin_layout Author
Orsiris
\begin_inset Quotes eld
\end_inset
Ozy
\begin_inset Quotes erd
\end_inset
de Jong
\end_layout
\begin_layout Date
26 November 2014
\end_layout
\begin_layout Standard
\begin_inset CommandInset href
LatexCommand href
name "http://www.netpower.fr/osync"
target "http://www.netpower.fr/osync"
\end_inset
\end_layout
\begin_layout Standard
\begin_inset CommandInset line
LatexCommand rule
offset "0.5ex"
width "100col%"
height "1pt"
\end_inset
\end_layout
\begin_layout Standard
\begin_inset CommandInset toc
LatexCommand tableofcontents
\end_inset
\end_layout
\begin_layout Section
Introduction
\end_layout
\begin_layout Subsection
Quickstart guide
\end_layout
\begin_layout Standard
Osync is a command line two way synchronization tool for Linux / BSD / MacOSX
and Windows that tries to be the most reliable possible for automation.
\end_layout
\begin_layout Standard
A quickstart guide might be found in the README.md file.
\end_layout
\begin_layout Subsection
Basic synchronization concepts
\end_layout
\begin_layout Standard
Synchronization is usually found in two flavors, filesystem sync and file
level sync.
While whole filesystem synchronization is generally a good way, it's also
very greedy in network ressources and is not easy to setup.
That's where file level sync comes in handy, where only some directories
need to be synced.
\end_layout
\begin_layout Standard
Now imagine you're syncing two remote offices of a same company.
If you're syncing a user's home directory or it's roaming profile as a
night task, the next day, the user will find it's roaming profile up to
date at the other office.
\end_layout
\begin_layout Standard
But what would happen if two users work on the same file in a public folder,
at the same time, on both offices ? Most sync software would stop sync
and ask what to do.
Others might simply deleted the oldest version of the file, even if it
was modified on both sides.
\end_layout
\begin_layout Standard
Also, what would happen if a user uploads too much new data ? If the link
between both offices cannot handle enough data transfer in a given time,
any other sync task won't be run, and the sync would continue during the
day, when bandwidth is necessary elsewhere.
\end_layout
\begin_layout Standard
What would happen if a power fault occurs while synchronization is going
on ?
\end_layout
\begin_layout Subsection
What exactly can do Osync
\end_layout
\begin_layout Standard
Osync is designed to synchronize two folders on both local and / or remote
systems.
\end_layout
\begin_layout Standard
It is time controlled, which means you can decide how much time it should
spend on a sync task before stopping it.
\end_layout
\begin_layout Standard
It can resume failed or stopped sync tasks, or totally restart the sync
task if more earlier runs failed.
\end_layout
\begin_layout Standard
It can keep an earlier version of a file in case of a conflict.
It can also keep multiple earlier versions.
\end_layout
\begin_layout Standard
It can soft delete files, meaning if a user deletes a file on a replica,
it will keep a copy of that file on the other replica in a
\begin_inset Quotes sld
\end_inset
recycle bin
\begin_inset Quotes srd
\end_inset
.
\end_layout
\begin_layout Standard
It will automatically clean old files (soft deleted and conflict backed
up ones) after a defined amount of days.
\end_layout
\begin_layout Standard
It will check local disk space before trying to sync.
\end_layout
\begin_layout Standard
It will send a warning email including the whole sync process execution
log if a warning or error is triggered.
\end_layout
\begin_layout Standard
Pre-processing and post-processing commands can be launched on local and
/ or remote systems (usefull to launch snapshot, flush or virtual machines
standby scripts).
\end_layout
\begin_layout Standard
Multiple concurrent instances of osync can be run as long as they don't
sync the same replicas at the same time.
\end_layout
\begin_layout Standard
Osync can use rsync or ssh tunnel compression to gain bandwidth.
Bandwidth can also be limited.
\end_layout
\begin_layout Standard
It can run in quicksync mode for the impatient (nothing to configure except
the replica paths), or with a full blown config file.
\end_layout
\begin_layout Standard
You may run Osync manually, schedule its runs with cron, or have it monitor
a directory as a daemon.
\end_layout
\begin_layout Standard
Osync has been succesfully tested on RHEL / CentOS 5, CentOS 6, Centos 7,
Debian Linux 6.0.7, Linux Mint 14, FreeBSD 8.3, Mac OS X, and Windows using
MSYS environment.
\end_layout
\begin_layout Subsection
How Osync tries to resolve sync issues
\end_layout
\begin_layout Standard
Let's get back to the example above, where Osync is used to sync two remote
offices with users' home directories.
\end_layout
\begin_layout Standard
Now imagine a user uploaded 100GB of data, whereas the WAN link can only
handle 60GB of data transfer every night (let's say a regular maintenance
night goes from 10:00 pm to 6:00 am).
\end_layout
\begin_layout Standard
Now if cron launches Osync every night at 10:00 pm, and Osync is configured
to run for maximum 10 hours, it would stop at 6am, after having transferred
60GB.
\end_layout
\begin_layout Standard
Then, on the next day, it would transfer the remaining 40GB from 10:00 pm
to about 3:30am.
\end_layout
\begin_layout Standard
Also, if you run chained instances of Osync, one per user, you can decide
how much time Osync would spend per user.
So if a user uploads too much data, Osync will keep running for that user
for a given amount of time, and then runs for the next user so everyone
will get it's data synced, regarless if the first user has uploaded too
much data.
\end_layout
\begin_layout Subsection
Naming in this document
\end_layout
\begin_layout Standard
Osync's goal is to synchronize two directories, that can be hosted on the
same computer or two different ones.
\end_layout
\begin_layout Standard
The computer that runs Osync must hold at least one of the two directories,
and will be called the
\emph on
local system.
\end_layout
\begin_layout Standard
The first directory on the local system is called the
\emph on
master replica
\emph default
.
\end_layout
\begin_layout Standard
The second directory, called the
\emph on
slave replica
\emph default
can be hosted on the
\emph on
local system
\emph default
, or on another computer which will be called the
\emph on
remote system
\emph default
.
In that case, the
\emph on
local system
\emph default
will connect to the
\emph on
remote system
\emph default
through an ssh tunnel and synchronize both
\emph on
master
\emph default
and
\emph on
slave replicas
\emph default
.
\end_layout
\begin_layout Section
Prerequisites
\end_layout
\begin_layout Subsection
General packages
\end_layout
\begin_layout Standard
The following packages are needed on both local and remote systems.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
rsync coreutils
\end_layout
\end_inset
\end_layout
\begin_layout Subsection
File synchronization
\end_layout
\begin_layout Standard
File sync tasks don't need any special configurations.
You only have to worry about your sync user having enough filesystem permission
s to read / write on both replicas.
\end_layout
\begin_layout Standard
A good way is to make your user member of the files' group that has full
permissions.
\end_layout
\begin_layout Standard
Another way to achieve this is using ACLs if your filesystem supports them.
You can add the following permissions for user "syncuser" on directory
"/home/web".
Setting a default rule will add rights on new files.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# setfacl -mR d:g:r-x,g:r-x /home/web
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Be aware that ACLs are tricky and default group permissions serve as mask
for ACLs.
Make always sure you can read your data with your sync user:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# su syncuser
\end_layout
\begin_layout Plain Layout
$ cat /master/replica/test.file
\end_layout
\end_inset
\end_layout
\begin_layout Subsection
\begin_inset CommandInset label
LatexCommand label
name "sub:Performing-superuser-backups"
\end_inset
Performing superuser sync
\end_layout
\begin_layout Standard
Osync may be run as superuser, which should always be avoided by granting
the right permissions to a dedicated sync user.
Nevertheless, there are some cases where running as superuser is necessary
to ensure backups of certain system files.
\end_layout
\begin_layout Standard
In order to be able to use the sudo command without having to enter a password,
you’ll need to modify the local and / or remote system to allow the following
commands to be run as superuser: rsync, du, find, mkdir, rm, echo and cat.
\end_layout
\begin_layout Standard
Edit the file /etc/sudoers and add the following
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
syncuser ALL= NOPASSWD:/usr/bin/rsync
\end_layout
\begin_layout Plain Layout
syncuser ALL= NOPASSWD:/usr/bin/du
\end_layout
\begin_layout Plain Layout
syncuser ALL= NOPASSWD:/bin/find
\end_layout
\begin_layout Plain Layout
syncuser ALL= NOPASSWD:/bin/mkdir
\end_layout
\begin_layout Plain Layout
syncuser ALL= NOPASSWD:/bin/rm
\end_layout
\begin_layout Plain Layout
syncuser ALL= NOPASSWD:/bin/mv
\end_layout
\begin_layout Plain Layout
syncuser ALL= NOPASSWD:/bin/echo
\end_layout
\begin_layout Plain Layout
syncuser ALL= NOPASSWD:/bin/cat
\end_layout
\end_inset
\end_layout
\begin_layout Standard
You might check the right paths to your commands with the following example:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# which rsync
\end_layout
\end_inset
\end_layout
\begin_layout Standard
You'll also need to disable requiretty in /etc/sudoers by adding the following
line:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
Defaults:backupuser !requiretty
\end_layout
\end_inset
\end_layout
\begin_layout Standard
You should be aware that there is a minor risk with having rsync command
run as superuser.
A user who can run rsync command as superuser can upload any file he wants
to the system, including a tweaked /etc/sudoers or /etc/passwd file.
Please read chapter
\begin_inset CommandInset ref
LatexCommand ref
reference "sub:Enhancing-remote-backup"
\end_inset
to secure your installation.
\end_layout
\begin_layout Subsection
Remote sync
\end_layout
\begin_layout Standard
Remote synchronization is done through an SSH tunnel.
To be able to establish such a tunnel without having to enter a password,
you’ll have to generate a pair of private and public RSA keys.
\end_layout
\begin_layout Standard
The private part is kept by the computer that initiates the connection,
the local system..
The public part is kept on the remote system.
\end_layout
\begin_layout Standard
The following steps will be required to generate a ssh key.
Please create a dedicated sync user and log in as that user on the local
system to perform the following actions.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
$ ssh-keygen -t rsa
\end_layout
\end_inset
\end_layout
\begin_layout Standard
This should create two files named ~/.ssh/id_rsa and ~/.ssh/id_rsa.pub
\end_layout
\begin_layout Standard
The remote system should also have a dedicated sync user (
\begin_inset Quotes eld
\end_inset
syncuser
\begin_inset Quotes erd
\end_inset
in this example).
Both local and remote users don't need to have the same name.
\end_layout
\begin_layout Standard
Copy the public part of the RSA pair to the remote system with scp (replace
22 with your ssh port number if needed).
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
$ scp -p 22 ~/.ssh/id_rsa syncuser@remotesystem.tld:/home/syncuser/.ssh/authorized_
keys
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Make sure the file is readable by the syncuser on the remote system.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# chmod 600 /home/syncuser/.ssh/authorized_keys
\end_layout
\begin_layout Plain Layout
# chown syncuser:root /home/syncuser/.ssh/authorized_keys
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Now you should be able to login as "syncuser" on the remote system without
any password.
You can try to remotely login by entering the following on the local system:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
$ ssh -p 22 syncuser@remotesystem.tld
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Be aware that only the user that generated the ssh key can remotely log
in.
\end_layout
\begin_layout Standard
You may optionnaly enhance remote login security by applying chapter
\begin_inset CommandInset ref
LatexCommand ref
reference "sub:Enhancing-remote-backup"
\end_inset
methods.
\end_layout
\begin_layout Subsection
Mail transport agent
\end_layout
\begin_layout Standard
You should make sure your system can send emails so Osync can warn you if
something bad happens.
Osync will use mutt or mail command.
Please make sure you can send a test mail with at least one of the following
commands run by your sync user:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
$ echo "your test message" | mutt -x -s "This is a test message" your@mail.tld
\end_layout
\begin_layout Plain Layout
$ echo "your test message" | mail -s "This is a test message" your@mail.tld
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Check your antispam if you don't get your message.
If you still don't get your message, check your distributions documentation
about the mail command.
\end_layout
\begin_layout Standard
If you run on windows environment, please make sure you can launch sendemail.exe
(found
\begin_inset CommandInset href
LatexCommand href
name "here"
target "http://caspian.dotconf.net/menu/Software/SendEmail/"
\end_inset
).
\end_layout
\begin_layout Subsection
\begin_inset CommandInset label
LatexCommand label
name "sub:Enhancing-remote-backup"
\end_inset
Enhancing remote system security
\end_layout
\begin_layout Standard
We may want to secure a password-less ssh access by removing non necessary
services offered by SSH.
Edit the file ~/.ssh/authorized_keys created earlier and add the following
line in the beginning of the file:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-pty
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Also, we may want to prevent any host except of our remote system to passwordles
s connect.
Add the following line:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
from=*.my.remote.servers.domain.tld
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Your authorized_keys file should look like this:
\end_layout
\begin_layout Standard
\begin_inset listings
lstparams "breaklines=true"
inline false
status open
\begin_layout Plain Layout
from="*.mydomain.tld",no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-
pty ssh-rsa yourkey== syncuser@host.tld
\end_layout
\end_inset
\end_layout
\begin_layout Subsection
More security enhancing
\end_layout
\begin_layout Standard
We may also restrict the ssh session to only a couple of commands we'll
need.
Osync comes with a script called
\emph on
ssh_filter.sh
\emph default
that will only execute commands Osync might send.
Once again edit your authorized_keys file and add the following.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
command="/usr/local/bin/ssh_filter.sh"
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Your file should then look like this:
\end_layout
\begin_layout Standard
\begin_inset listings
lstparams "breaklines=true,showstringspaces=false"
inline false
status open
\begin_layout Plain Layout
from="*.mydomain.tld",no-port-forwarding,no-X11-forwarding,no-agent-forwarding,no-
pty,command="/usr/local/bin/ssh_filter.sh" ssh-rsa yourkey== syncuser@remotesyste
m.tld
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Copy then the script ssh_filter.sh to /usr/local/bin on the remote system.
Don't forget to make it executable and make it owned by root
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# chmod 755 /usr/local/bin/ssh_filter.sh
\end_layout
\begin_layout Plain Layout
# chown root:root /usr/local/bin/ssh_filter.sh
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Now, only the commands
\begin_inset Quotes eld
\end_inset
find, du, rsync, echo and sudo
\begin_inset Quotes erd
\end_inset
may be executed via the ssh tunnel.
You may enable / disable the usage of sudo command by editing the following
value in the ssh_filter.sh script:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
SUDO_EXEC=yes
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Also, adding remote pre- and postexecution commands in your configuration
files will not work if you use the ssh filter.
You'll have to add your main command in ssh_filter.sh.
Example if you want to perform remote snapshots you'll have to allow one
of the following:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
CMD1=zfs
\end_layout
\begin_layout Plain Layout
CMD2=xfs
\end_layout
\begin_layout Plain Layout
CMD3=lvm
\end_layout
\end_inset
\end_layout
\begin_layout Subsection
\begin_inset CommandInset label
LatexCommand label
name "sub:More-security-(or"
\end_inset
Security for the paranoid
\end_layout
\begin_layout Standard
Executing rsync as superuser is a security risk.
A way to prevent rsync usage allowing only a symlink to be executed.
Thus, a attacker script using rsync would not work.
This kind of security is called
\begin_inset Quotes eld
\end_inset
security by obscurity
\begin_inset Quotes erd
\end_inset
and should generally not be the only security process, but makes any attack
harder.
First, let's create a symlink to rsync called let's say o_rsync
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# ln -s $(which rsync) $(dirname $(which rsync))/o_rsync
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Now edit ssh_filter.sh and change the following value:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
RSYNC_EXECUTABLE=o_rsync
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Also, edit RSYNC_EXECUTABLE value on any of your sync configuration files
and you're done.
\end_layout
\begin_layout Section
Running Osync in quicksync mode
\end_layout
\begin_layout Standard
You must first download a copy of osync to your computer, and make it executable.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# chmod +x osync.sh
\end_layout
\end_inset
\end_layout
\begin_layout Standard
You might consider copying osync to
\emph on
/usr/local/bin
\end_layout
\begin_layout Standard
Then you might just launch it to sync two local dirs like this:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# ./osync.sh --master=/path/to/dir1 --slave=/path/to/dir2
\end_layout
\end_inset
\end_layout
\begin_layout Standard
You also may want to sync a remote directory.
\end_layout
\begin_layout Standard
You may specify an alternate SSH port directly in the URI.
When ommited, SSH port 22 is used.
\end_layout
\begin_layout Standard
Also, if not set, the default RSA key will be read from ~/.ssh/id_rsa
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# ./osync.sh --master=/path/to/dir1 --slave=ssh://remoteuser@remotehost.com//path/t
o/dir2
\end_layout
\begin_layout Plain Layout
# ./osync.sh --master=/path/to/dir2 --slave=ssh://remoteuser@remotehost.com:22//pat
h/to/dir2 --rsakey=/home/user/.ssh/other_key
\end_layout
\end_inset
\end_layout
\begin_layout Section
Running Osync with a full blown configuration file
\end_layout
\begin_layout Standard
Running Osync with a configuration will do just the same as in quicksync
mode, except the fact that you have much more control of what's going on.
\end_layout
\begin_layout Standard
A sample configuration file is called sync.conf and is included with osync.
You may edit this file to fit your needs.
\end_layout
\begin_layout Standard
Every option of the configuration file is explained in the appendix.
\end_layout
\begin_layout Standard
Once you've setup a file according to your needs, you may go for a test
run.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# ./osync.sh /path/to/my_sync.conf --dry --verbose
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Osync should now enumerate which changes will be done on both sides.
\end_layout
\begin_layout Standard
If everything worked out right, you might process the actual sync process.
\end_layout
\begin_layout Standard
Remember that a full configuration file specifies a maximum execution delay.
Initial sync tasks can take a huge amount of time depending on bandwidth
between replicas, in that case you might add parameter --no-maxtime to
your first sync run so execution time won't be enforced.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# ./osync.sh /path/to/my_sync.conf --no-maxtime
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Creating a regular sync scenario is quite simple as long as you don't schedule
two times the same sync task in a shorter time span than your HARD_MAX_EXEC_TIM
E_TOTAL value.
Just create a crontab entry and add parameter --silent so your local mailbox
won't get filled up.
Example, having async scheduled every hour in /etc/crontab
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
00 * * * * localsyncuser /usr/local/bin/osync.sh /home/localsyncuser/your_sync.con
f --silent
\end_layout
\end_inset
You may find the sync log under /var/log/osync-version-your_sync.log or under
the current directory if /var/log is not writable.
\end_layout
\begin_layout Section
Running Osync on file changes
\end_layout
\begin_layout Subsection
By hand
\end_layout
\begin_layout Standard
Osync may also run in file monitor mode.
In this mode, osync monitors the master replica, and runs a synchronization
everytime the is file activity on master replica.
With this mode, you do not need cron anymore.
Be aware that only master replica is monitored, and slave replica sync
updates only occur when master replica modifications happen.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# ./osync.sh /path/to/my_sync.conf --on-changes
\end_layout
\end_inset
\end_layout
\begin_layout Subsection
As a system service
\end_layout
\begin_layout Standard
If you plan to run Osync on a regular basis in file monitor mode, you might
consider installing it as a system service.
\end_layout
\begin_layout Standard
From the directory you downloaded Osync, run the following to make Osync
a service:
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
# cp osync.sh /usr/local/bin
\end_layout
\begin_layout Plain Layout
# cp osync-srv /etc/init.d
\end_layout
\begin_layout Plain Layout
# mkdir /etc/osync
\end_layout
\begin_layout Plain Layout
# cp sync.conf /etc/osync
\end_layout
\begin_layout Plain Layout
# service osync-srv start
\end_layout
\begin_layout Plain Layout
# chkconfig osync-srv on
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Osync then scans for *.conf files in /etc/osync and will run an instance
per configuration file.
\end_layout
\begin_layout Standard
Service control just works like with standard system services.
\end_layout
\begin_layout Section
Configuration appendix
\end_layout
\begin_layout Subsection
Quicksync only command line parameters
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--master=
\begin_inset Quotes srd
\end_inset
\begin_inset Quotes srd
\end_inset
Master replica path.
Will contain state and backup directory (is mandatory)
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--slave Local or remote slave replica path.
Can be a ssh uri like ssh://user@host.com:22//path/to/slave/replica (is
mandatory)
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--rsakey Alternative path to rsa private key for ssh connection to slave
replica
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--sync-id Optional sync task name to identify this synchronization task
when using multiple slaves
\end_layout
\begin_layout Subsection
Universal command line parameters
\end_layout
\begin_layout Standard
When run without any parameter, Osync will show usage.
\end_layout
\begin_layout Standard
Both quicksync and config file modes can take the following optional parameters:
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--dry Will make osync run a simulation only
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--silent Will run osync silently, to be used in a cron schedule
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--verbose Will run osync with detailed output, including changed and deleted
files lists on both sides
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--stats Will add rsync transfer statistics to verbose output
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--no-maxtime Will disable MAX_EXEC_TIME checks, so a task can take as long
as it needs.
This is usefull for performing initial big sync operations
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--force-unlock Will override any existing active or dead locks on master
and slave replica
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--on-changes Will launch a sync task after a short wait period if there
is some file activity on master replica.
You should try daemon mode instead
\end_layout
\begin_layout Labeling
\labelwidthstring 00.00.0000
--help Will print Osync version and usage
\end_layout
\begin_layout Subsection
Full list of configuration file parameters
\end_layout
\begin_layout Standard
Set this to whatever you want to identify your sync task.
This value is also in the log name and in the warning mails.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
SYNC_ID=name_of_your_sync
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Master directory to sync (master replica), must be on the system you're
running osync on.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
MASTER_SYNC_DIR="/some/path"
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Slave directory to sync (slave replica), can be on the same system you're
running osync on or another remote system, reachable via an SSH tunnel.
\end_layout
\begin_layout Standard
Slave directory can be a SSH uri like
\begin_inset Quotes sld
\end_inset
ssh://user@host.com:1234//some/other/path
\begin_inset Quotes srd
\end_inset
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
SLAVE_SYNC_DIR="/some/other/path"
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Location of the private RSA key.
If left empty, the default path
\begin_inset Quotes sld
\end_inset
~/.ssh/id_rsa
\begin_inset Quotes srd
\end_inset
will be used.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
SSH_RSA_PRIVATE_KEY=~/.ssh/id_rsa
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Tells osync to create master or slave directories if they don't exist.
Default is no.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
CREATE_DIRS=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
By default, leaving this empty sets the log file to /var/log/osync_SYNC_ID.log.
You might change this to specify a personalized log file.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
LOGFILE=""
\end_layout
\end_inset
\end_layout
\begin_layout Standard
List of directories to exclude in sync task on both sides (rsync patterns,
wildcards will work).
Paths are relative to both replicas paths.
List is separated by PATH_SEPARATOR_CHAR defined below.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
RSYNC_EXCLUDE_PATTERN="tmp;archives;whatever path"
\end_layout
\end_inset
File that contains the list of directories or files to exclude from sync
on both sides.
Leave this empty if you don't want to use an exclusion file.
This file has to be in the same directory as the config file.
Paths are relative to sync dirs.
One element per line.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
RSYNC_EXCLUDE_FROM="exclude.list"
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Path separator char for RSYNC_EXCLUDE_PATTERN, you might change this in
the unholy case that your filenames contains semicolons.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
PATH_SEPARATOR_CHAR=";"
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Generate an alert if master or slave replicas have less space than the following
given value in kilobytes.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
MINIMUM_SPACE=10240
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Bandwidth limit in kilobytes / second.
Leave this to zero to disable limitation.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
BANDWIDTH=0
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Synchronization tasks may be executed as root if you enable the following
parameter.
See prerequisites in chapter
\begin_inset CommandInset ref
LatexCommand ref
reference "sub:Performing-superuser-backups"
\end_inset
.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
SUDO_EXEC=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Paranoia option.
Don't change this unless you read chapter
\begin_inset CommandInset ref
LatexCommand ref
reference "sub:More-security-(or"
\end_inset
.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
RSYNC_EXECUTABLE=rsync
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Enable / disable ssh compression.
Leave this enabled unless your connection to remote system is high speed
(LAN)
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
SSH_COMPRESSION=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Ping remote host before launching synchronization.
Be sure the host responds to ping.
Failing to ping will skip current task.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
REMOTE_HOST_PING=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Itemize
Check for internet access by pinging one or more hosts before launching
remote sync task.
Leave this empty do disable the check.
Failing to ping will stop execution.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
REMOTE_3RD_PARTY_HOST="www.kernel.org"
\end_layout
\end_inset
\end_layout
\begin_layout Itemize
Misc settings
\end_layout
\begin_layout Standard
Preserve ACLs.
Please check that your filesystem supports ACLs and is mounted with it's
support or rsync will get you loads of errors.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
PRESERVE_ACL=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Preserve Xattr.
The same applies as for ACLs
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
PRESERVE_XATTR=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Transforms symlinks into referent files/dirs when syncing replicas.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
COPY_SYMLINKS=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Treat symlinked dirs as dirs.
CAUTION: This also follows symlinks outside of the replica root.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
KEEP_DIRLINKS=no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Preserve hard links.
Make sure source and target FS can manage hard links or you will lose them.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
PRESERVE_HARDLINKS=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Use rsync compression for file transfers.
Leave this disabled unless your're not using SSH compression.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
RSYNC_COMPRESS=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Maximum execution time (in seconds) for sync process.
Soft value generates a warning only.
Hard value generates a warning and stops sync task.
\end_layout
\begin_layout Standard
You may set this to 0 to disable time checks.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
SOFT_MAX_EXEC_TIME_FILE_TASK=7200
\end_layout
\begin_layout Plain Layout
HARD_MAX_EXEC_TIME_FILE_TASK=10600
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Minimum time (in seconds) in file monitor /daemon mode between modification
detection and sync task in order to let copy operations finish.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
MIN_WAIT=60
\end_layout
\end_inset
\end_layout
\begin_layout Itemize
Conflict and deletion option
\end_layout
\begin_layout Standard
Enabling this option will keep a backup of a file on the target replica
if it gets updated from the source replica.
Backups will be made to .osync_workdir/backups
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
CONFLICT_BACKUP=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Keep multiple backup versions of the same file.
Warning, This can be very space consuming.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
CONFLICT_BACKUP_MULTIPLE=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Osync will clean backup files after a given number of days.
Setting this to 0 will disable cleaning and keep backups forever.
Warning: This can be very space consuming.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
CONFLICT_BACKUP_DAYS=30
\end_layout
\end_inset
\end_layout
\begin_layout Standard
If the same file exists on both replicas, newer version will be synced.
However, if both files have the same timestamp but differ, CONFILCT_PREVALANCE
sets winner replica.
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
CONFLICT_PREVALANCE=master|slave
\end_layout
\end_inset
\end_layout
\begin_layout Standard
On deletition propagation to the target replica, a backup of the deleted
files can be kept.
Deletions will be kept in .osync_workdir/deleted
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
SOFT_DELETE=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Osync will clean deleted files after a given number of days.
Setting this to 0 will disable cleaning and keep deleted files forever.
Warning: This can be very space consuming.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
SOFT_DELETE_DAYS=30
\end_layout
\end_inset
\end_layout
\begin_layout Itemize
Resuming options
\end_layout
\begin_layout Standard
Try to resume an aborted sync task
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
RESUME_SYNC=yes|no
\end_layout
\end_inset
Number maximum resume tries before initating a fresh sync.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
RESUME_TRY=2
\end_layout
\end_inset
\end_layout
\begin_layout Standard
When a pidlock exists on slave replica that does not correspond to master's
sync-id, force pidlock removal.
Be carefull with this option if you have multiple masters.
\end_layout
\begin_layout Standard
\begin_inset listings
lstparams "breaklines=true"
inline false
status open
\begin_layout Plain Layout
FORCE_STRANGER_LOCK_RESUME=no
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Keep partial uploads that can be resumed on next run, experimantal feature.
This can be very usefull if big files must get updated though slow links.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
PARTIAL=no
\end_layout
\end_inset
\end_layout
\begin_layout Itemize
Alert Options
\end_layout
\begin_layout Standard
List of alert mails separated by spaces
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
DESTINATION_MAILS="your@alert.tld"
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Windows (MSYS environment) only mail options (used with sendemail.exe from
Brandon Zehm)
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
SENDER_MAIL="alert@your.system.tld"
\end_layout
\begin_layout Plain Layout
SMTP_SERVER=smtp.your.isp.tld
\end_layout
\begin_layout Plain Layout
SMTP_USER=optional_smtp_user
\end_layout
\begin_layout Plain Layout
SMTP_PASSWORD=optional_smtp_password
\end_layout
\end_inset
\end_layout
\begin_layout Itemize
Execution hooks
\end_layout
\begin_layout Standard
Commands can will be run before and / or after sync process (remote execution
will only happen if REMOTE_SYNC is set).
Multiple commands can be semicolon separated.
\end_layout
\begin_layout Standard
Command(s) to run locally before sync process starts.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
LOCAL_RUN_BEFORE_CMD=""
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Command(s) to run locally if sync process finishes.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
LOCAL_RUN_AFTER_CMD=""
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Command(s) to run on remote system before sync process starts.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
REMOTE_RUN_BEFORE_CMD=""
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Command(s) to run on remote system if sync process finishes.
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
REMOTE_RUN_AFTER_CMD=""
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Max execution time of commands before they get force killed.
Leave 0 if you don't wan't this to happen.
Time is specified in seconds.
MAX_EXEC_TIME_PER_CMD_BEFORE=0
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
MAX_EXEC_TIME_PER_CMD_AFTER=0
\end_layout
\end_inset
\end_layout
\begin_layout Standard
Stops Osync execution if one of the above commands fail
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
STOP_ON_CMD_ERROR=yes|no
\end_layout
\end_inset
\end_layout
\begin_layout Section
Troubleshooting
\end_layout
\begin_layout Standard
Osync has been tested successfully on multiple systems for a wide variety
of sync plans.
Please check the following steps before requesting help.
\end_layout
\begin_layout Subsection
Local-local sync
\end_layout
\begin_layout Standard
Osync logs every of it's actions to /var/log/osync-version-your_sync_id.log
(or current directory if /var/log is not writable).
\end_layout
\begin_layout Standard
Please check the log file if something went wrong.
\end_layout
\begin_layout Standard
You might try running osync as root to check if your problem is filesystem
permission related.
\end_layout
\begin_layout Standard
You might add --verbose option to see what actually happens.
\end_layout
\begin_layout Subsection
Local-remote sync
\end_layout
\begin_layout Standard
Remote synchronization is a bit more tricky.
\end_layout
\begin_layout Standard
You might check that you can log in remotely with the command
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
$ ssh -p 22 remotesyncuser@remotehost.tld
\end_layout
\end_inset
Also, you might check that you can use rsync command remotely
\end_layout
\begin_layout Standard
\begin_inset listings
inline false
status open
\begin_layout Plain Layout
$ ssh -p 22 remotesyncuser@remotehost.tld rsync --help
\end_layout
\end_inset
You can temporarily disable ssh security by removing lines you added in
chapter
\begin_inset CommandInset ref
LatexCommand ref
reference "sub:Enhancing-remote-backup"
\end_inset
.
Additionnaly, you can check ssh_filter log in ~/.ssh/ssh_filter.log on the
remote system.
You might try running osync with SUDO_EXEC to check if your problem is
user permission related.
\end_layout
\begin_layout Standard
\begin_inset CommandInset line
LatexCommand rule
offset "0.5ex"
width "100col%"
height "1pt"
\end_inset
\end_layout
\end_body
\end_document
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