MD1967
Contributor
Contributor

Helping vCenter balance VMs on hosts with different RAM specs

Hi guys.

I was wondering how I could balance out VMs over 8 production hosts that have similar CPU clocks and cores but 5 of have 113GB of RAM and 3 that have 190GB RAM.

DRS seems to balance out the CPU loads fine but I am seeing that the 3 higher cpu hosts have 30% of RAM utilised, while the 5 older hosts have 70%.

Does vCenter 4.1 have issues with different spec'd hosts and is this improved in vSphere 5 ?

Thanks in advance for any pointers or info.

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4 Replies
Troy_Clavell
Immortal
Immortal

If DRS sees the cluster as balanced it will do no more.  You can check the summary tab of your cluster and looks a the VMware DRS chart.  If you're in the green DRS is doing it's job.  With that said, you can try to set your migration threshold a bit more aggressive or manually balance the cluster yourself using vMotion

MD1967
Contributor
Contributor

Thanks for that Troy. I thought this would be the case.


Do you know if vCenter 5 has a different way of distributing ? I know I can set up rules to place the high RAM/low CPU (if there is such a thing) servers on the higher RAM hosts to balance it a bit myself, but I was just wondering if there was another way.


Thanks

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Troy_Clavell
Immortal
Immortal

vCenter 5 and DRS will not make that much of a difference as far as DRS is concerned. You're best bet is to manually balance the load if setting your migration threshold more aggressive doesn't work.

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weinstein5
Immortal
Immortal

no vcenter works the same way -  DRS's purpose is to insyre that each VM is receiving the necessary resources not to make the sam number if VMs or the same amount of CPU/Memory is being used on each hosr in the cluster -

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