Solved

Hyper-V 2012 R2 and Storage QOS

Posted on 2014-01-06
10
488 Views
Last Modified: 2014-11-12
Hello ,


Im testing the Storage QOS feature of Hyper-V 2012 R2 .

As we know a simple SAS disk has about 120-150 IOPS max.

So i have a Virtual Machine and i have limit it to 150 iops.

The results i take are far worst from a physical disk with the same IOPS. Copies are veeeery slow and also if i try to copy something and in the same time try to open lets say control panel everything becomes unresponsive until the copy finishes. If i remove the qos everything works great.

Is this standard behavior ?

Thanks
0
Comment
Question by:Anestis Psomas
  • 5
  • 5
10 Comments
 
LVL 117
ID: 39761446
I would not expect to see the IOPS in a virtual machine to equal the maximum number of IOPS for a single physical disk, because the I/O is virtualised inside the VM.

e.g. the virtual disk (vhd) is created on the pyhsical disk, and you are testing inside the VHD.

So I would not consider this to be strange but completey normal.
0
 

Author Comment

by:Anestis Psomas
ID: 39761483
Hello ,

Maybe you are right in case i have my VM stored inside a single physical Disk .

In my case i have a Fibre SAN with multiple disks and a lot of IOPS .

Also if we do not expect to see the IOPS of a physical disk then what do we expect? The term IO  is the same in physical and virtual disks.

Thanks for your help .
0
 
LVL 117

Accepted Solution

by:
Andrew Hancock (VMware vExpert / EE MVE) earned 500 total points
ID: 39761567
Physical I/O and Virtual I/O is less.

Also the VM which is under a hypervisor will also perform worse, than if the server was physical.

What you can expect, is that it will be less, and not equal to physical I/O performance.

If you want physical I/O performance, present the disks via RAW Mapped LUN.
0
 

Author Comment

by:Anestis Psomas
ID: 39761592
So if i want to emulate the iops of a physical SAS disk how much iops i must give to a VM ?


Thanks
0
 
LVL 117
ID: 39761604
if you have a single physical SAS disks, e.g. 100 IOPS (after calculating), you would need to give the VM, 100 IOPS.

But this may require you to, use RAID and JBOD techniques to increase the datastore IOPS.
0
How to run any project with ease

Manage projects of all sizes how you want. Great for personal to-do lists, project milestones, team priorities and launch plans.
- Combine task lists, docs, spreadsheets, and chat in one
- View and edit from mobile/offline
- Cut down on emails

 

Author Comment

by:Anestis Psomas
ID: 39761749
The storage i use for my tests of qos is a 3PAR Storeserv . I have present cluster volumes to my cluster from this storage. This is a fibre channel storage and it can give me maximum 16000 IOPS .

Thanks
0
 
LVL 117
ID: 39761761
So that should be plenty for your VM.
0
 

Author Comment

by:Anestis Psomas
ID: 39761810
Hello ,

of Course its plenty but this is not the point of the conversation .

 As i write earlier the question is why the 150 iops limit i put into the VM doesn't have the same behavior with 150 iops on a physical disk as the IOPS as a metric is identical in both Virtual Hard Disk and Physical Disk.
0
 
LVL 117
ID: 39761818
Okay, I think I undersatand you have limited a VM to 150 IOPS

How is the copy being performed across the network?

or local file copy?
0
 

Author Comment

by:Anestis Psomas
ID: 39761827
It is a local file copy .
0

Featured Post

Netscaler Common Configuration How To guides

If you use NetScaler you will want to see these guides. The NetScaler How To Guides show administrators how to get NetScaler up and configured by providing instructions for common scenarios and some not so common ones.

Join & Write a Comment

Sometimes drives fill up and we don't know why.  If you don't understand the best way to use the tools available, you may end up being stumped as to why your drive says it's not full when you have no space left!  Here's how you can find out...
Exchange server is not supported in any cloud-hosted platform (other than Azure with Azure Premium Storage).
This tutorial will walk an individual through the process of configuring basic necessities in order to use the 2010 version of Data Protection Manager. These include storage, agents, and protection jobs. Launch Data Protection Manager from the deskt…
In this video tutorial I show you the main steps to install and configure  a VMware ESXi6.0 server. The video has my comments as text on the screen and you can pause anytime when needed. Hope this will be helpful. Verify that your hardware and BIO…

758 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

22 Experts available now in Live!

Get 1:1 Help Now