Using rsync for data transfer and synchronization
Rsync is a data transport tool that can be used much like the scp command.
When transferring data,
rsync checks the difference between the source and target files and only transfers the parts that have changed. This makes
rsync suitable for:
- Synchronizing folders. Using
cpwould copy and transfer everything, while
rsyncwill only copy and transfer the modifications.
- Transferring larger files.
rsynccan be set to save progress, so if the transfer is interrupted it can be resumed at the same point.
The Basic command syntax of rsync is:
rsync -options source target
If the data source or target location is a remote site, it is defined with syntax:
However, both the target and source can also be located on the same machine. In that case you can just give directory paths to source and target sites.
The table below lists the most commonly used options:
||recurse into directories|
||Use archive mode: copy files and directories recursively and preserve access permissions and time stamps.|
||ssh||Specify the remote shell to use.|
||Show what files would be transferred.|
||Keep partially transferred files.|
||Show progress during transfer.|
||same as --partial --progress|
So the command for transferring a local folder to Puhti,while showing the progress and keeping partially transferred files, would be:
rsync -rP /path/to/local/folder firstname.lastname@example.org:/path/to/target
This would either:
- create a folder on Puhti at /path/to/target/folder, if the folder was not present before. In this case, everything in the folder will be transferred
- synchronize the source and target folders, if the folder already exists on Puhti. In this case, only changes we have made will be transferred
And the same thing in reverse:
rsync -rP email@example.com:/path/to/target/folder /path/to/local
rsync will always overwrite any changes made to the target, even if they are newer than the source.