Not sure why hardly anyone picked up on this cool youtube movie about Storage IO Control(SIOC), but I figured it was worth posting. SIOC is probably one of the coolest version coming to a vSphere version in the near future. Scott Drummonds wrote a cool article about it which shows the strength of SIOC when it comes to fairness. One might say that there already is a tool to do it and that’s called per VM disk shares, well that’s not entirely true… The following diagrams depict the current situation(without…) and the future(with…) :
As the diagrams clearly shows, the current version of shares are on a per Host basis. When a single VM on a host floods your storage all other VMs on the datastore will be effected. Those who are running on the same host could easily, by using shares, carve up the bandwidth. However if that VM which causes the load would move a different host the shares would be useless. With SIOC the fairness mechanism that was introduced goes one level up. That means that on a cluster level Disk shares will be taken into account.
There are a couple of things to keep in mind though:
- SIOC is enabled per datastore
- SIOC only applies disk shares when a certain threshold(Device Latency, most likely 30ms) has been reached.
- The latency value will be configurable but it is not recommended for now
- SIOC carves out the array queue, this enables a faster response for VMs doing for instance sequential IOs
- SIOC will enforce limits in terms of IOPS when specified on the VM level
- No reservation setting for now…
Anyway, enough random ramblings… here’s the movie. Watch it!
For those with a VMworld account I can recommend watching TA3461.
The soundtrack really rocks ! So the feature of course…
excelent video, very clear for all guys out there, i think SIOC its a great feauture, hope we can see soon a deeper description, how it will work etc.
I could be wrong but I see this more as VMware’s “enterprise” focus. SMBs could possibly have this problem but this might be less likely to happen since they don’t have as many hosts or VMs that do a lot of I/O etc.
It’s not enabled by default, why?? If it’s so helpful. 🙂
I wonder if the new memory compression feature would be more helpful??
Thank you, Tom
It’s a major improvement. The competition lucks a feature like this…
An easy way to control disk access per host.
Music is excellent.. Like… -:)
Great feature. I been testing 4.1 Beta and had no idea that’s even in there. I guess I should review the release notes better next time, and the virus he had looks awesome does anybody know the name of this virus and where I can get it? And is the virus dangerous does it create any problems or is it for show? If it does not mass anything up it would be a great prank on the wife and co-workers.
the disk latency test utility. where do i find that ??
I was’nt sure I would like this site since it was about Storage IO Control, the movie » Yellow Bricks but I was wrong and thought it was cool and found it on AOL . Thanks and I’ll be back as you update.
as I read in another replay the soundtrack rocks.
BUT due to this soundtrack this movie is BLOCKED in Germany, have not found a way to see it.
Seems I must wait till I travel to another country.
RESUME: background sound can give problems with the law, depending on country!
Hi Duncan,
we have citrix vm’s with non persistant disks. Our service desk members shut down these VM’s ungracefully several times a day (upto 20 times for 30 VM’s) for various issues like sessions hanging and being unresponsive. Can this cause Disk I/O errors.
I think now limits of sioc are there , sure for 4.1 . resource mgmt guide page 43 point 6 says change limits .
krishnaji