Poor disk performance on win2012 R2 VM with RDP

[BegeX]

Hello!

I need to set up the Remote Desktop Services on a Windows 2012 R2 machine under Proxmox. After installing operating system all goes fine, the applications work well. But right after installing remote desktop services the io performance reduces by half. After that i've tried to use the image of this VM with Hyper-V and got normal performance, as for deployed directly on hardware.

However, setting io priority to the performance test process to 'high' with ProcessHacker (processhacker.sourceforge.net) restores the performance up to normal.

After removing RDS the io performance also becomes normal.

The results are the same for 4.4, 5.0 and 5.1 Proxmox

Thanks in advance,
Alex

 

[fireon]

What storage, storageformat, number of HDD/SSD's, Raidlevel, Memory, CPU do you use? Please post also the output of

pveperf /your/storagepath

 

[BegeX]

pveperf /
CPU BOGOMIPS: 41600.24
REGEX/SECOND: 2702171
HD SIZE: 335.42 GB (rpool/ROOT/pve-1)
FSYNCS/SECOND: 152.98
DNS EXT: 97.30 ms
DNS INT: 2.42 ms

I've tried to disable sync on dataset for testing purpose, and got
FSYNCS/SECOND: 32743.24
but nevertheless guest performance stayed poor.


ZFS, ext4 gives the same results. Different models of Intel Xeon and Core-iX. Memory from 4 up to 64 Gb.

But it seems i found the reason - the Fair Share subsystem of windows 2012 (virtualization.vanbragt.net/index.php/articles/general-articles/fairshare-of-resources-in-rd-session-host). Turning off the fair share for disk after installing windows RDS makes the performance normal. Windows 2008 also works fine, but it doesn't have the Fair Share for IO.

 

[bofh]

this is really interresting.
my guess in the dark is that hyperv kinda pravirtualisation for win server helps it out quiet a bit.

wonde rif tthe same happens in vmware or virtualbox

personally i run only 2 rds enviroments on kvm
both i have split local storage.
one raid 10 array spinning disks for storage and one raid 10 array with ssds.
i put all system images (c drive) on the ssd array

gives me 5 sec bootup time on 2012r2 )
also never had an issue with i/o or anything there. but thats no promox thingis, all pure libvirt kvms on debian 8