amurph
Contributor
Contributor

ESXi swap?

I've posted a few threads on here relating to some vmotion and performance issues I'm having in ESXi. While browsing through performance graphs I've noticed that some, but not all, of my ESXi hosts have some high values for "memory swap used". Memory usage on the hosts themselves is around 30% give or take. If this was ESX3.5 I would add memory to the service console but in ESXi I'm not sure what to do. I can add memory reservations to various system resource pools but I don't know where to add it. The System resource pool has an unlimited limit, so I don't see how adding resources there would help.

My original problem was that some vm's would not vmotion, while others would, even between the same two hosts. I've noticed that, at least with some of the vm's, if I cold migrate them to a host that is not swapping, they will vmotion to another host that is not swapping. Of course, I'm hesitant to believe that this is more than a coincidence as other vm's will vmotion between two swapping hosts just fine, but I'm trying to fix all of my issues here.

Any ideas?

0 Kudos
2 Replies
kooltechies
Expert
Expert

Hi,

You need to go with the memory reservation route only which will certainly prevent excessive swapping as you will gurantee access of physical memory to the VM. You can reservations at Resource pool level or directly at the Virtual machine level. You can decide that by selecting the most frequent VM who is swapping out extensively or you can decide if multiple VM's under one resource pool is doing that then increase at the resource pool level.

Thanks,

Samir

P.S : If you consider this information as helpful please consider awarding points

Blog : http://thinkingloudoncloud.com || Twitter : @kooltechies || P.S : If you think that the answer is correct/helpful please consider rewarding points.
0 Kudos
weinstein5
Immortal
Immortal

setting a memory reservation will not prevent swapping - it will just gaurantee a fixed amount of memory when there is contention - if contention continues swapping will occur. One of the things that will cause swapping is setting limits - do you have any limits set? Either for the VMs or on Resource pools? On to the vmotion problems - Do you receive any errors when you try to vmotion? Does it just time or do you get an out of resource error?

If you find this or any other answer useful please consider awarding points by marking the answer correct or helpful

If you find this or any other answer useful please consider awarding points by marking the answer correct or helpful
0 Kudos