Curious observation on backup speed


Well-Known Member
Nov 1, 2003
Northern Ontario, Canada
cPanel Access Level
Root Administrator

I just recently switched from 'Legacy Backup' to the new 'Backup'. As far as I can tell, I have configured the new backup for the same behaviour as the legacy system was. I have a new server with an SSD drive, which is pretty quick. The legacy backups were taking 29 minutes to run and were running about 12:30 am. The new backup takes 47 minutes to run and starts at about 2:00 am.

Is this difference in speed of completion to be expected? At about 150%, it's actually a fairly significant difference.


Staff member
Apr 11, 2011

You should first review the backup log in /usr/local/cpanel/logs/cpbackup/ to verify if the backup process was paused at any point in time due to the Extra CPUs for Server Load setting.

You can also browse to the "Compression" tab in "WHM >> Tweak Settings" if you want to adjust some of the compression options to increase performance (Ensure you have sufficient resources to do so). The available options are documented at:

Tweak Settings - Documentation - cPanel Documentation

In addition, under the "System" tab, you may find the following option helpful:

"I/O priority level at which nightly backups are run (Maximum: 7)"
You must compile ionice with your kernel to use this option. ionice manages I/O scheduling for processes on your system. Specifying a lower value for this option gives the process a higher priority. This option can accept integer values between 0 and 7.

Thank you.
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Well-Known Member
Jul 9, 2015
cPanel Access Level
Root Administrator
I have a powerful server, but I still have max compression and limit it to one zip thread to keep any performance impact to a minimum. I don't mind if backups run for 8 hours, as long as they don't impact anything.

I would guess it's one of the settings cPanelMichael mentioned though.
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