Service Affecting increase in disk io after installing Cloud Linux
Looking for some advice, thoughts or opinions. I'm running a WHM/cPanel server with about a 180GB of data in /home I installed Cloud Linux a few days ago. My backups used to run in about 6hrs now they are taking 12-15hrs. I have determined the cause to be a significant increase in disk io (see the attached image) You can see that starting on the 24th the disk io demand changed significantly which is when Cloud Linux was installed.
No changes were made to the backup configuration so its clearly a side effect of CL but does anyone have an idea's why?
I tried increasing the KB chunk to 512 last night thinking if it did compression in memory and it was to compress larger chunks it would have less frequent io, but I think that it had the opposite effect by the looks of today's stats. I plan to try reducing it down to the minimum 128 tonight and maybe reduce the number of pigz processes to 6 and see if that alleviates the demand, but I'd still like opinions and comments.
TECHNICAL HARDWARE DETAILS:
sda is a 1TB RAID10 array on a 3ware 9650SE-4LP
sdc is a 2TB drive on the motherboard
Server is a Dual E5410 8GB RAM
BACKUP CONFIGURATION:
Compressed Backups using the new cPanel implementation (not legacy)
COMPRESSIONS SETTINGS:
use pigz - yes
gzip compression level - minimum (1)
Number of pigz processes - 8
Number of kilobyte chunks per compression work unit - 512
Thanks
