If you use two Linux Servers with NFS Shares connect over Gigabit Interfaces for Backups, you perhaps remark performance problems on using rsync.
It does often pause transmissions or reach only a rate of 32Mb/s. That’s bad and waste time and energy.
After some Tests of running Backups with single files and compressed big archives, the scans of my tools like iftop, systat, iptraf found out that the used Option „rsync -avz“ was the bottle neck, cause the Data Rate break down at intervals. The „z“ compress option was described on howtos as must have for slower networks did not work like a „on the fly permanent transmission“. My two Test Servers use each 3 Gigabit bonded NIC Cards, if the rsync command compress the Files, they were first pulled to RAM Cache and compressed there later after a small pause send.
If you disable and remove the „z“ option and on used bash scripts as „batch run“ removing the „v“ Option too, i was able to send Data at range of 133MB/s.
On fast Network do:
$rsync -a /source/ /nfs-mounted-destination