vSphere 6 DRS not working as expected

[CaroKiel]

Hi,

We've got a brand new vSphere 6 environment with 27 VMs on a 2-node-cluster.

Both hosts are HP DL360 G9 with identical hardware and connected by redundant SAS to a HP MSA 2040.

All VMs are running fine and everything seems to be good, except that DRS is not working as expected.

As of today 26 of the 27 VMs are running on one host, while the second host nonly holds a single VM.

I can manually migrate VMs from one host to the other without any trouble, but the load balancing seems not to work. DRS is set to fully automated and I even tried to set the Migratio Threshold to "agressive (5)" but nothing happened at all.

When I look into the DRS faults list in the cluster properties, the list is empty. A look into "Memory Utilization" shows >50% usage on the first node and nearly no utilizationon the sencond one.

Does anybody have an idea what we did wrong or why it doesnt load balance the VMs between the hosts?

All the best from Germany

Caroline

[brunofernandez1]

what about if you put one ESXi Server in maintenance mode?

are the vms migrated to the second node?

[CaroKiel]

Hi Brunofernandez,

yes, if I put one node into maintenance mode, all machines are moved automatically.

Caroline

[brunofernandez1]

so the requirements are met for DRS. The vms can be moved around...

have you maybe configured some affinity rules?

when you click on the cluster you should have a button where you can run DRS manually. is something migrating when you click on it?

i mean this button on the right: Run DRS:

http://i.ytimg.com/vi/h6Ma6TLKlto/maxresdefault.jpg

[CaroKiel]

Hi,

no, no affinity rules at all.

And yes, if I click on "run DRS now", two VMs were moved. But only two out of 27.

By the way, the Summary tab of the cluster states "imbalanced"...

Caroline

[CaroKiel]

And, as stated, we're talking about vSphere 6.0, so no "full client", only web...

[brunofernandez1]

sorry this was the only picture i've found on the internet

it's clear that in vsphere 6 you have to work with the webclient.

can you make some printscreens of your actual configuration. do you use ressource pools?

[CaroKiel]

Here you go...

If you need anything else, just let me know.

And no, we're not using Resource Pools...

Caroline

[brunofernandez1]

hmmm seems to be everything ok

does the monitor shows still imbalanced when DRS moves the two VMs?

do you have configured limits, reservations or shares on the vms?

[CaroKiel]

Yes, the images are brand new and taken after the two VMs were moved.

No, we haven't configured any reservations, shares etc. Everything is mplain and simple, like out of the box.

Caroline

[brunofernandez1]

my recommendation until I come up with something new: let the vcenter do his job this weekend.

as I know DRS is not working all the time...maybe in the next days he will balance the VMs.

actually i don't know anything more to troubleshoot...

[CaroKiel]

Hi,

I'll do so and wait, whether something is happening on the weekend.

Thank you very much and have a nice weekend.

All the best

Caroline

[Linjo]

There might not be any contention on the host so DRS find no reason to move the VM:s to the other host.

If you create more vm:s you should see this even out eventually.

// Linjo

[Mustang1941]

Hey CaroKiel,

I've seen the same with my environment. vCenter 6 with esxi 6 host. One host will be in an alarm state for memory usage near 90%, that host is running 40 of 42 vm's. You would expect vCenter DRS to Balance the load. I've noticed this several times in the past months since upgrading to 6. Move the DRS aggressiveness up but it still doesn't balance them. I don't recall having this issue in 5.1. Since we setup emails when our host get alarms, we get awaken at night for no real reason as DRS should balance it out and be done with it. Have you found anything on this issue? Ill probably open a ticket, spend hours with support to hear its working as expected. Been there done that!