Low Fsync/Sec (Win Server 16 VM bad performance)

nasarhon

New Member
Oct 15, 2018
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Hi guys,
I am quite new to the virtualization world. So the starter for the problem is that my Windows Server 2016 guest is guite slow.

The physical machine is a i7 7700 and it has 16 GB RAM. I have two vm one of them is a Win 7 (4 GB ram assigned) where I have no problem, the other one is the Windows Server 2016 (8 GB ram assigned there). The Proxmox PVE and the two guest are also located on the same harddisk, which is a Seagate Barracuda 2 TB 7200rpm disk.

So the Win Server is slow but I did not see any problem with the CPU usage or the RAM usage. I did the reading for the last couple of days, and here is my average "pveperf" when both vm are running:

root@host:~# pveperf
CPU BOGOMIPS: 54528.00
REGEX/SECOND: 3586561
HD SIZE: 93.99 GB (/dev/mapper/pve-root)
BUFFERED READS: 181.66 MB/sec
AVERAGE SEEK TIME: 10.09 ms
FSYNCS/SECOND: 40.47
DNS EXT: 94.94 ms
DNS INT: 51.27 ms (...)

root@host:~# pveperf
CPU BOGOMIPS: 54528.00
REGEX/SECOND: 3835356
HD SIZE: 93.99 GB (/dev/mapper/pve-root)
BUFFERED READS: 146.65 MB/sec
AVERAGE SEEK TIME: 10.78 ms
FSYNCS/SECOND: 35.63
DNS EXT: 118.02 ms
DNS INT: 56.48 ms (...)

I guess my biggest problem has to be the FSYNCS/SEC. So I tried couple of helpful tricks: without cache and write back also, none of them has changed the results.

Can someone guide me a bit, where to go from here?

Thank you in advance!
 
are you running zfs?

No I don't, I did not do any special config for the drive controller, so everything is standard. But that is another question in me: is it beneficial to run zfs for such a bacis setup, and if it is, is it possible to configure after everthing is set up or is it too late so to say? is there any guide/tutorial for that?
 
What are you using for a raid controller? I'm guessing on board sata ports. I would highly suggest a raid controller with a bbu. I switched from onboard sata to a hardware raid controller and performance increased more than 10 fold. I use a simple lsi 9260 4i I purchased from ebay for around $30.
 
What are you using for a raid controller? I'm guessing on board sata ports. I would highly suggest a raid controller with a bbu. I switched from onboard sata to a hardware raid controller and performance increased more than 10 fold. I use a simple lsi 9260 4i I purchased from ebay for around $30.

You are right, on board. Thanks for the advice and naming the device!

My Proxmox VE and the two vm are also located on the same hdd, will I be able to start the physical machine out of the box with the raid controller or is there anything to take care of in order to use it?
 
You will likely have two options:

1. Backup all of your data format disks and build raid array using the new controller
2. Leave your existing stuff in place, use new drives to build raid array then migrate your vm's to the new storage.

When I build hosts. I usually put the base os on a mirrored pair of drives and then create a separate raid array for my vm's usually raid 10 but if I have low iop application I may use raid 5 or 2nd mirrored pair. This allows me to loose the entire host os array and still have my data.
 
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