VM Performance

[zombiezach8]

I am wondering if I configured anything wrong but I have horrible performance on my VMs. Actually just for windows. I am using virtIO and installed the drivers network, storage etc. and it's having horrible lag/latency. I've looked in device manager and all devices are installed + tried updating. Windows task manager has system faults and it stays at 0% occasionally going to 1-2% but upwards of 20% when I go to download a 1GB test file I tried disabling network driver but I went to do a trace and I found it was something called Storport doing alot of dpc latency? Just sitting idle nothing open but a program to check latency is extremely high @ 1% cpu

I've tried the latest and newest virtIO drivers. The server usage is extremely low and IO delay is 0.98%.

OS: Windows Server 2012 R2
Edit: I also tried LatencyMon but it just freezes the VM
Edit 2: I turned cached to Write Back and the latency is now stable around 1100ms instead of jumping randomly upwards of 10K+ ms. Still when downloading a 1gb test file the system interrupts goes upward to 20% or so while the latency is way more stable but jumps around to 4000.

 

[Vasu Sreekumar]

If you have more than two windows 2012 KVM you really need SSD drives.

With SATA drives, it is going to be dead slow.

Always use Virtio drivers for everything, that gives best performance. For drives sue SCSI Virtio drivers.

 

[guletz]

If you have more than two windows 2012 KVM you really need SSD drives.

It is not so impotant how many X VM do you have(at least if you can allocated some decent resurces). Important is what proceses do you run in each VM and what are the resurces need it for each of them.

 

[Vasu Sreekumar]

For windows 2012 it really matters even if you don't run anything in it.

Windows 2012 takes lot of resources when it starts.

 

[guletz]

For windows 2012 it really matters even if you don't run anything in it.

In my case, without any SSD for windows 2012, the cpu is around 2-6 %(1 month average, 2 vCPU ), and about 75% RAM usage(6 GB allocated). And I running a print-server with many print jobs/minutes. On another windows 2012 VM, is almost the same regarding CPU, and RAM(8GB allocated) with a MSSQL DB, and a sql client application.
I can gues I am only a lucky guy

 

[Vasu Sreekumar]

You just have 2 VM, Upto 2 or 3 it is ok.

SSD is needed if you need more than 3.

 

[GadgetPig]

@zombiezacvh8 :

What is your current ProxMox/VM cpu & storage setup? Single disk or Raid1/ Raid 10? How much total memory does server have? If you're running standard SATA, make sure BIOS storage is also set to AHCI or RAID/AHCI instead of IDE emulation.

If you SSH into ProxMox, do you have any error messages (in RED) when you type "dmesg -T"?

In my case I noticed a VM on my ZFS pool running much slower than usual, so I ran dmesg -T and found one of my disks showing I/O errors (even though it passed smart long test)

sample below:
[Tue Mar 6 22:43:21 2018] print_req_error: I/O error, dev sdd, sector 346994904