Optimizing performance - valuable tips and tricks welcomed!

[TomasHermansson]

I have a PVE cluster with two nodes and I'm eager to maximize their performance. I've initiated with pveperf to establish a baseline. What steps can I take to enhance their efficiency further?

PVEPERF shows the following

CPU BOGOMIPS:	23 998.92
REGEX/SECOND:	3 067 258
HD SIZE:	50.68 GB (/dev/mapper/pve-root)
BUFFERED READS:	261.99 MB/sec
AVERAGE SEEK TIME:	0.21 ms
FSYNCS/SECOND:	751.72
DNS EXT:	43.79 ms
DNS INT:	37.62 ms (local)

CPU BOGOMIPS:	27 201.80
REGEX/SECOND:	2 867 825
HD SIZE:	64.06 GB (/dev/mapper/pve-root)
BUFFERED READS:	237.17 MB/sec
AVERAGE SEEK TIME:	0.19 ms
FSYNCS/SECOND:	715.12
DNS EXT:	40.44 ms
DNS INT:	11.79 ms

 

[Dunuin]

Disable mitigations in case you don't care about security.

 

[TomasHermansson]

Disable mitigations in case you don't care about security.

What aspect of security will be affected by disabling mitigations ? I do have an pfSense infront of the PVE's... are the mitigations redundant then?

 

[leesteken]

Make sure you have a third vote (third node or QDevice) as this forum is full of problems with two-node clusters.
Maybe get enterprise SSDs and a faster local DNS server (I don't know why pveperf does not show buffered reads and seek time for me):

CPU BOGOMIPS:      217597.44
REGEX/SECOND:      5246912
HD SIZE:           189.70 GB (tpool/test)
FSYNCS/SECOND:     10506.35
DNS EXT:           26.35 ms
DNS INT:           1.18 ms (lan)

 

[Dunuin]

What aspect of security will be affected by disabling mitigations ? I do have an pfSense infront of the PVE's... are the mitigations redundant then?

See all the hardware vulnerabilities like Spectre, Meltdown and so on. You can't fix the hardware, so you will have to fix them in software and this costs performance. You could disable those fixes and run the system with these unpatched hardware vulnerabilities by adding "mitigations=off" to your bootloader. But this for example would allow VM A to access data stored in RAM by VM B and similar. So it breaks the isolation.