Hi,

I am using Rsync cmd for copying files between sorce and target box daily. It have to check incremental chunks out of 20 GB and copy the changed chunks from source and paste it to target. It takes approx. 10 - 20 Mins. During this period CPU in source and target is reaching up to 100% utilization.
Kindly, suggest me how to control CPU utilization or what else can be done.

Thats because while copying from rsync command it tries to retrieve the list of files that you are copying and because you have too many files so in memory its utilize too much ram as well as resources to copy them to new place.. You will have to distribute the task among small task..

You will have to divide your operation for rsync in bash script like this way..
Like for example this is your script
rsync /source root@1.1.1.1:/source_backup/

THEN
Create a bash script and apply it in this way

#!/bin/bash
rsync /source/[0-9]* root@1.1.1.1:/source_backup/
rsync /source/[a-h]* root@1.1.1.1:/source_backup/
rsync /source/[i-p]* root@1.1.1.1:/source_backup/
rsync /source/[q-z]* root@1.1.1.1:/source_backup/

Or, man nice

that's the behavior of rsync. you can do chunk rsync to avoid such usage.

What you mean by "chunk rsync" here? Could you please elaborate?