Admission control and ResPool reservation

[DanieleFiore201]

Dear guys,

as long as i do set reservation to my res pools (with limits) i really find difficult to check how many slots are used if i select "host failures the cluster tolerates" admission control setting.

Normally slots are calculated based on VM reservation, but what about reservation assigned to ResPools?

Then i'm checking the Runtime Info on my cluster and i do not have clear some values :

Total slot in the cluster =>ok

used slots =>ok

available slots =>what does mean ?

failover slots =>what does mean ?

For these 2 values i went on vmware documentation but it was not that clear to me..

Many thanks in advance.

Daniele

[RanjnaAggarwal]

Check this out:-

http://www.yellow-bricks.com/vmware-high-availability-deepdiv/#HA-admission

[DanieleFiore201]

Hi i checked this out but it did not anwer to my questions especially assigning reservations to res pools besides single VMS.

Any other  ?

[RanjnaAggarwal]

Slots are not calculated based on the resource pool reservation these are only calculated based on the vm reservation

[sysxperts]

Also keep in mind that it's generally recommended to use "Percentage of cluster resources..." for admission control

[sysxperts]

Also see http://blog.scottlowe.org/2007/12/04/calculating-vmware-ha-failover-capacity/

[DanieleFiore201]

I have been told by a certified trainer that the 1st AC policy is the most secure even if too conservative as it is a mathematic calculation done by vmware tools.

My approach is to handle reservations with res pools instead to VM level.

[RanjnaAggarwal · Accepted solution]

I tested it slots are calculated based on vm reservation not the Resource Pool Reservation

Example:-

Total Number of slots = 22

Used Slots = 4 (Depends on Numbers of VM Running)

Available Slots = 7

Failover Slots = 11 ( Depends on How many hosts failure cluster can tolerate) if it is 1 and we have 2 node cluster then it is 50% of the total slots. Means you can use it according to this example you can only power on 11 VM's now not more than that.

If still it is not clear tell me please

[DanieleFiore201]

Many thanks very well explained, you awarned some points.

Daniele