TacoSauce
Enthusiast
Enthusiast

Limit IOPs with sioc but no results....

Jump to solution

L.s.,

I've  limited the IOPs of two vitual disks of a VM to 300 IOPs but I still  see read peaks of 1500 IOPs? Why are these peaks not limited? Anyone  ideas?

sioc-iops-002.jpg

We've enabled SIOC on our datastores and the vmware tools in the specific vm are current.

cheers,

Wouter

0 Kudos
1 Solution

Accepted Solutions
peetz
Leadership
Leadership

Please see the following blog post for an explanation of how to use IOPS limits:

http://v-front.blogspot.de/2011/08/how-to-throttle-that-disk-io-hog.html

- Andreas

Twitter: @VFrontDe, @ESXiPatches | https://esxi-patches.v-front.de | https://vibsdepot.v-front.de

View solution in original post

0 Kudos
6 Replies
Paul11
Hot Shot
Hot Shot

To Limit the IOPs for a VM you must set the Limit for every Disk. If one Disk has "Unlimited", the IOPs-Limit for all disks of this VM is unlimited.

Than look at the Disk-performance of the VM ("Read requests" and "Write Requests") and divide the value of the Summation by 20 because the Monitoring Intervall is 20 seconds. Than you will see, that the Limit is working.

Paul

jr195
Contributor
Contributor

The graph posted is by virtual disk, so any iops limit should be visible there -- the OP is not asking about limiting iops for an entire VM.

I have also seen this behavior and still wonder why.

And as I understand it, SIOC and iops limits are completely separate -- SIOC enforces disk shares when the congestion threshold is reached, and an iops limit simply sets a hard limit on the number of ios a given vmdk can perform every second. I do remember reading some VMware documentation where the two were confused, though. SIOC requires the Enterprise Plus license, but you should be able to set iops limits even with a Standard license.

TacoSauce
Enthusiast
Enthusiast

Hi Paul,

We have another vm with two disks, one is limited to 150 IOPs and the other disk is unlimited. The graph shows that the IOPs for the specific disk are  limited, unless we've a second unlimited disk!

With regards,

Wouter

sioc-iops-003.jpg

0 Kudos
TacoSauce
Enthusiast
Enthusiast

Thnx for your reply! I still hope someone can help us out!

Cheers

0 Kudos
peetz
Leadership
Leadership

Please see the following blog post for an explanation of how to use IOPS limits:

http://v-front.blogspot.de/2011/08/how-to-throttle-that-disk-io-hog.html

- Andreas

Twitter: @VFrontDe, @ESXiPatches | https://esxi-patches.v-front.de | https://vibsdepot.v-front.de
0 Kudos
TacoSauce
Enthusiast
Enthusiast

Thnx Andreas,

I managed the limits succesfully.

0 Kudos