===== rsync =====

From one Folder to another Folder (Content only) 
<code bash>
rsync -a <SOURCE_FOLDER>/ <DEST_FOLDER>/
</code>

One Remotefolder content into destination Folder (can be ./)
<code bash>
rsync -a <USERNAME>@Server:/<SOURCE_FOLDER>/* <DEST_FOLDER>/
</code>

== rsync out of Memory ==

When syncing a lot of files, rsync build a large file-cache in memory. This can go thus far, that the system is swaping and will become unresponsable.
To limit the file-caching avild the ''**-H**''-paraemeter and use:

<code bash>
--no-inc-recursive
</code>
==== Idea of parallel rsync ====

The following command can be used to run rsync over multiple threads in parallel. This can tremendously speedup file copy from one disk or computer node on a network to the next.

In the example below, the main variables used are:

**''$thread=24''** -- Use 24 threads. Adjust this depending on the capacity of the systems involved. Set to 0 for xargs to maximize this value.

**''$src=/src/''** -- This represents the source path of the directory of contents you wish to copy. It's important to pay attention to the ending /.

**''$dest=/dest/''** -- This is the destination path for the files to be copied.
<code bash>
$threads=24; $src=/src/; $dest=/dest/ rsync -aL -f"+ */" -f"- *" $src $dest && (cd $src && find . -type f | xargs -n1 -P$threads -I% rsync -az % $dest/% )
</code>