Config Layer 4: Default Config

You can simply choose from a set of three default implementations which are: rsync, rsyncssh and direct.

To sync a local directory using the default rsync behavior, just add this to a config file:

sync {
   source = "DIRNAME",
   target = "DIRNAME"

The order of the arguments is of no importance. If target is a local directory, take care that it is an absolute pathname. You can add multiple syncs that way. The source directories may be identical or differ without problems. source is an universal parameter that must be given for every sync. All other sync parameters can differ depending on the behavior selected. Optionally you can override the default or settings values maxDelays or maxProcesses per Sync.

One can also skip the initial rsync process by setting the default init function to false:

sync {
    source = "DIRNAME",
    target = "DIRNAME",
    init   = false

This is an optimization which can be dangerous; so, please use it only if you are sure that source and target are synchronized when Lsyncd is started.

The default behaviors you can select from are following:

Shared Settings

Following settings are shared between all defaults:

Name Description
source Source directory
crontab See section Periodic Full-Sync


The default rsync configuration will aggregate events up to delay seconds or 1000 separate uncollapsible events, which ever happens first. Then it will spawn one Rsync with a filter of all files that changed. The filter list is transmitted to Rsync trough a pipe. A call from Lsyncd to Rsync will thus look like this:

/usr/bin/rsync -ltsd --delete --include-from=- --exclude=* SOURCE TARGET

You can change the options Rsync is called and the Rsync binary that is call with the rsync parameter.


sync {
    source    = "/home/user/src/",
    target    = "",
    delay     = 15,
    rsync     = {
        binary   = "/usr/local/bin/rsync",
        archive  = true,
        compress = true

Additional settings: | Name | Description | |—————–|————-| | batchSizeLimit | Files larger then this limit should not be batched into on transfer. Only makes sense with processes > 1 which prevents rsyncssh |

Below is a table of options for the rsync parameter. Please have a look at the Rsync documentation for an in depth explanation.

parameter = TYPE default value comment
acls = BOOL false
append = BOOL false (Lsyncd >= 2.2.0)
append-verify = BOOL false (Lsyncd >= 2.2.0)
archive = BOOL false
backup = BOOL false (Lsyncd >= 2.2.0)
backup_dir = DIR false (Lsyncd >= 2.2.0)
binary = FILENAME "/usr/bin/rsync" Lsyncd calls this binary as rsync
checksum = BOOL false
chmod = STRING (Lsyncd >= 2.2.0)
chown = USER:GROUP (Lsyncd >= 2.2.0)
compress = BOOL false
copy_dirlinks = BOOL false (Lsyncd >= 2.2.0)
copy_links = BOOL false
cvs_exclude = BOOL
dry_run = BOOL false
exclude = PATTERN TABLE of PATTERNs also allowed
excludeFrom = FILENAME
executability = BOOL false
existing = BOOL false (Lsyncd >= 2.2.0)
filter = TABLE of STRINGS (Lsyncd >= 2.2.3)
group = BOOL false
groupmap = STRING (Lsyncd >= 2.2.0)
hard_links = BOOL false
ignore_times = BOOL false
inplace = BOOL false (Lsyncd >= 2.1.6)
ipv4 = BOOL false
ipv6 = BOOL false
links = BOOL true
one_file_system = BOOL false
owner = BOOL false
password_file = FILENAME (Lsyncd >= 2.1.2)
perms = BOOL false
protect_args = BOOL true
prune_empty_dirs = BOOL false
quiet = BOOL false
rsync_path = PATH (path to rsync on remote host)
sparse = BOOL false
suffix = SUFFIX (Lsyncd >= 2.2.0)
temp_dir = DIR
times = BOOL true
update = BOOL false
usermap = STRING (Lsyncd >= 2.2.0)
verbose = BOOL false
whole_file = BOOL false
xattrs = BOOL false
_extra = TABLE of STRINGS. If absolutely needed, additional arguments can be specified as a TABLE of STRINGS(example: { "--omit-dir-times", "--omit-link-times" }). Note that the underscore highlights this as workaround. If you need something that is not covered by the above options, please request it via a feature request on the project website. Most notably, do not add -r for recursive or -a which implies recursive, since Lsyncd will handle that by itself. Additionally do not add -R for relative, which will ruin Lsyncd <-> Rsync communication.


This configuration differs from the standard rsync configuration in that it uses ssh commands to move files or directories locally at the target host instead of deleting and transferring again. This configuration does spawn Rsync processes like default.rsync but additionally will spawn /usr/bin/ssh HOST mv ORIGIN DESTINATION commands.

Different to default.rsync it does not take an uniform target parameter, but needs host and targetdir separated.

Rsync’s options can be changed with the rsync parameter like in default.rsync described above.

Additional to that ssh can be configured via the ssh parameter.

binary = FILENAME Lsyncd calls this binary as ssh (default: /usr/bin/ssh)
identityFile = FILE Uses this file to identify for public key authentication.
options = TABLE A table of addition extended options to pass to ssh's -o option.
port = PORT Adds --port=PORT to the ssh call.
_extra = STRING TABLE Similar to rsync._extra this can be used as quick workaround if absolutely needed.


settings {
    logfile = "/var/log/lsyncd.log",
    statusFile = "/var/log/lsyncd-status.log",
    statusInterval = 20

sync {
   rsync = {
     archive = true,
     compress = false,
     whole_file = false
   ssh = {
     port = 1234

Please note the comma between the rsync parameter set and the ssh parameter set.

Caution If you are upgrading from 2.0.x, please notice that settings became a function from a variable, so you MUST delete the equal sign ‘=’ between settings and the {.

Lsyncd will call xargs on the remote host to handle multiple tasks in a single connection. Xargs options can be specified by the xargs parameter.

binary = FILENAME Lsyncd calls this binary as xargs on the remote host (default: /usr/bin/xargs)
delimiter = DELIMITER delimiting character to separate filenames. By default the 0 character is used. Very old holds may need newline instead.
_extra = STRING TABLE By default { '-0', 'rm -rf' }. Remove the -0 if you chose newline delimiter instead. Otherwise leave it as is.


sync {
    source    = "/home/user/src/",
    host      = "",
    targetdir = "~/trg/",
} can be used to keep two local directories in sync with better performance than using default.rsync. uses (just like default.rsync) rsync on startup to initially synchronize the target directory with the source directory. However, during normal operation uses /bin/cp, /bin/rm and /bin/mv to keep the synchronization. All parameters are just like default.rsync.


sync {,
    source  = "/home/user/src/",
    target  = "/home/user/trg/"


Two additional parameters can be specified to sync{}:

excludeFrom = FILENAME loads exclusion rules from this file, on rule per line
exclude = LIST loads exclusion rules from this list of strings

Exclusion rules are modeled after rsync’s exclusion patterns but are a bit simpler. Lsyncd supports these features:


sync {
    source    = "/home/user/src/",
    targetdir = "/home/user/dst/",
    exclude = { '_.bak' , '_.tmp' }


By default Lsyncd will delete files on the target that are not present at the source since this is a fundamental part of the idea of keeping the target in sync with the source. However, many users requested exceptions for this, for various reasons, so all default implementations take delete as an additional parameter.

Valid values for delete are:

delete = true Default. Lsyncd will delete on the target whatever is not in the source. At startup and what's being deleted during normal operation.
delete = false Lsyncd will not delete any files on the target. Not on startup nor on normal operation. (Overwrites are possible though)
delete = 'startup' Lsyncd will delete files on the target when it starts up but not on normal operation.
delete = 'running' Lsyncd will not delete files on the target when it starts up but will delete those that are removed during normal operation.


New in: 2.3.0

Lsyncd is able to start and manage external programs to provide a tunnel for data transfer. Additionally it can spawn multiple connections and load-balance connections among them. A tunnel is created through the tunnel function.

<figure class="highlight"><pre><code class="language-lua" data-lang="lua"><span class="n">sync</span> <span class="p">{</span>
    <span class="n">default</span><span class="p">.</span><span class="n">rsync</span><span class="p">,</span>
    <span class="n">tunnel</span>    <span class="o">=</span> <span class="n">tunnel</span> <span class="p">{</span>
        <span class="n">command</span> <span class="o">=</span> <span class="p">{</span><span class="s2">"ssh"</span><span class="p">,</span> <span class="s2">"-N"</span><span class="p">,</span> <span class="s2">"-L"</span><span class="p">,</span> <span class="s2">"localhost:5432:localhost:873"</span><span class="p">,</span> <span class="s2">"tunnel@testmachine"</span><span class="p">},</span>
    <span class="p">}</span>
    <span class="n">target</span>    <span class="o">=</span> <span class="s2">"rsync://localhost:5432/projects"</span><span class="p">,</span>
    <span class="n">source</span>    <span class="o">=</span> <span class="s2">"/home/user/src/"</span><span class="p">,</span>
<span class="p">}</span></code></pre></figure>

You can then set the shell for the tunnel user to /bin/false and configure the rsyncd server side appropriately.

Valid arguments for tunnel are:

Argument Description Default Valid values
mode Mode in which the tunnel is run command command, pool
command Required Command to run nil Table of arguments
parallel How many connections to run. Only for pool mode 1 1+
retryDelay Seconds to wait until tunnel is restarted 10 Number
readyDelay Seconds after program start to consider tunnel up 5 Number
localhost Name of the local host variable localhost String

Pool Mode

In pool mode, lsyncd allocates a new local port which is then passed as variable to the host command. All variables can be substituded by ^variable syntax. See ../../../../examples/lrsyncssh-tunnel.lua for a extended configuration.

List of variables

Name Description
localport Port allocated for the selected connection
localhost Local hostname used. Default localhost


Run 2 tunnel ssh processes and 4 rsync processes at the same time. Use extra transfers for all files larger 30 MB.

sync {
    tunnel = tunnel {
        command = {"ssh", "-N", "-L", "localhost:^localport:localhost:873", "user@testmachine"},
        mode = "pool",
        parallel = 2,
    source = "/data/projects",
    target    = "rsync://localhost:^localport/projects",
    delay = 5,
    batchSizeLimit = 1024 * 1024 * 30,
    maxProcesses = 4

This example will open 2 ssh connections for port forwarding and load balance 4 parallel rsync processes in a round roubin fashion.

Workflow in Poolmodel

When a sync with a tunnel parameter is started, all events are queued until the tunnel reaches the UP state, which is when one successful tunnel process exists for at least readyDelay seconds. Dead tunnel processes are automatically restarted. When the tunnel process count drops to 0, tunnel falls back to the CONNECTING state. There is a retryDelay seconds delay between each attempt to restart the tunnel.

Once the tunnel is UP, a full transfer is initiated. Subsequent transfers are then load balanced over multiple connections.

Notes on Poolmode

Periodic Full-Sync

New in: 2.3.0

It is possible to trigger a full sync command from within lsync with the crontab feature. This requires that lua-crontab is installed on the system. The crontab configuration accepts a list of crontab patterns to which a full sync will be triggered.

sync {
    crontab = {
            -- does a full sync once a day at 3:00:01
            "1 0 3 * * *",

Field destination

Each field is seperated by " " and can contain multiple values seperated by ,.

Seconds 0-59 , - *
Minutes 0-59 , - *
Hours 0-23 , - *
Day of month 1-31 , - *
Month 1-12 or JAN-DEC , - *
Day of week 0-6 or SUN-SAT , - *