Hi,
I'm struggling with a particulare concept surrounding resource pools with custom shares and I'm wondering whether anyone can point me in the right direction.
If we have a scenario in which we have three resource pools, relating to service tiers, we can call them gold, silver and bronze. Each resource pool will contain a different number of virtual machines with a varying number of vCPUs and VRAM. To avoid the resource pool priority pie paradox (http://www.yellow-bricks.com/2010/12/14/shares-set-on-resource-pools/) I am intending on using a script to configure custom shares based on the number of vCPUs in the cluster and the amount of vRAM, giving a higher weighting to virtual machines in the gold and silver tiers.
However, and this is where I get a bit confused. Resource pools are set on a cluster wide basis but resource contention would be felt on a host basis. I could have a situation whereby I have 10 VMs in the gold resource pool, 20 VMs in the silver resource pool and 30 VMs in the bronze resource pool, with the resource pools configured with the following share levels:
GOLD 40000 shares (10 x 4000)
SILVER 40000 shares (20 x 2000)
BRONZE 30000 (30 x 1000)
However, an individual host might have 1 gold VM, 5 silver VMs and 15 bronze VMs. So my question is this. In the situation described above, are the CPU shares carved out as shown below?
1 GOLD VM receives 40000 shares
5 SILVER VMs receive 8000 shares each (40000 / 5)
15 BRONZE VMs receive 2000 shares each (30000 / 15)
This doesn't seem right to me, but as I said I am struggling with this a little bit!
Thanks in advance