Increasing performance on CentOS KVM's

rugby

Member
Oct 24, 2009
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Just out of curiosity, what is the best configuration for CentOS based VM's? I have 4 of them on my server with 8xsata drives in RAID10 and performance of them is not very good at times. CPU utilization is very low as is ram usage, but disk usage is very high as each server writes thousands of small files (They're all Kerio MailServers).

Currently I have them setup with IDE drives within the VM with e1000 nics, but at times we're experiencing network timeouts and slow email processing. We migrated from an EXi 3.5 server with 3 of these VM's and performance was fine, we just ran out of disk space.
 
Just out of curiosity, what is the best configuration for CentOS based VM's? I have 4 of them on my server with 8xsata drives in RAID10 and performance of them is not very good at times. CPU utilization is very low as is ram usage, but disk usage is very high as each server writes thousands of small files (They're all Kerio MailServers).

Currently I have them setup with IDE drives within the VM with e1000 nics, but at times we're experiencing network timeouts and slow email processing. We migrated from an EXi 3.5 server with 3 of these VM's and performance was fine, we just ran out of disk space.

what do you get with pveperf (only run if the system is not under load)? details about your raid controller?
 
what do you get with pveperf (only run if the system is not under load)? details about your raid controller?

I will run pveperf tonight when the load calms down a lot, I have a 3Ware 9650SE-8LP with 2x2TB 7200rpm Hitachi drives with raid 10.

Running pveperf right now under load gets me this:

pm01:~# pveperf
CPU BOGOMIPS: 72537.68
REGEX/SECOND: 458881
HD SIZE: 15.50 GB (/dev/pve/root)
BUFFERED READS: 174.55 MB/sec
AVERAGE SEEK TIME: 8.89 ms
FSYNCS/SECOND: 2167.14
DNS EXT: 2002.02 ms
DNS INT: 1999.73 ms (mydomain.com)

Here's pveperf run in the middle of the night:

pm01:~# pveperf
CPU BOGOMIPS: 72537.68
REGEX/SECOND: 450473
HD SIZE: 15.50 GB (/dev/pve/root)
BUFFERED READS: 302.56 MB/sec
AVERAGE SEEK TIME: 8.03 ms
FSYNCS/SECOND: 2435.43
DNS EXT: 1845.29 ms
DNS INT: 1858.86 ms (mydomain.com)

The KVM's are still up but email has slowed considerably. I cannot shut them down completely without somebody calling me.
 
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Here's an email today I got from my PVE

/etc/cron.daily/mlocate:
Warning: /var/lib/mlocate/daily.lock present, not running today.
run-parts: /etc/cron.daily/mlocate exited with return code 1


One a side note, one of my VM's had stopped delivering mail for some reason. I've had this happen 2-3 times since moving my VM's to PVE. Never had that issue on any other VM solution I've used. I had to restart the mailserver on the VM for it to restart sending. This makes me very nervous.