Using RSYNC (Remote Synchronization) on a slow network can be challenging due to the possible interruptions and inefficiencies caused by the network’s speed. Despite this, it can still be beneficial as RSYNC has been designed to support the copying of large amounts of data across networks efficiently by only transmitting the differences between source and destination files, rather than the entire files, thus saving both time and bandwidth.
When dealing with a slow network, there are several techniques to optimize the use of RSYNC:
1. Compress Files: RSYNC has an in-built feature that allows it to compress files before transferring them. By using the “-z” option, you can activate this feature which effectively lessens the amount of data that needs to be transferred.
```
rsync -az /source/directory/ user@destination:/destination/directory/
```
The “-a” option is for archive mode, ensuring that symbolic links, devices, attributes, permissions, ownerships, etc. are preserved.
1. Partial Transfers: When transferring large files over slow networks, there’s a high risk of the operation getting interrupted. For this, RSYNC has a “—partial” option allowing it to keep partially transferred files and continue from where it stopped in case of any interruptions.
```
rsync —partial /source/directory/ user@destination:/destination/directory/
```
1. Limit Bandwidth: RSYNC permits you to limit the bandwidth used for the transfer. This is useful in a slow network setting where other critical network activities are going on. The “—bwlimit” option followed by the desired speed in KBytes per second allows this.
```
rsync —bwlimit=200 /source/directory/ user@destination:/destination/directory/
```
This example limits the transfer rate to 200 KBytes per second.
These techniques are drawn from the RSYNC manual pages available in Unix-based systems and can also be found on various Linux related websites such as the Linux Manual Page (man7.org/linux/man-pages/man1/rsync.1.html) and The Geek Stuff (www.thegeekstuff.com/2011/01/rsync-exclude-files-and-folders).
Lastly, it’s also suggested to use a stable and reliable connection, despite its speed. As RSYNC can handle interruptions, a stable connection ensures that the interruptions are as few as possible.
Remember that while these techniques can enhance the performance of RSYNC over slow networks, the nature of such networks means that transfers will still take longer than on faster networks. Patience, thus, is key in such situations.
