VMware vSphere

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  • 1.  One VM how many slots?

    Posted Jul 11, 2013 05:05 PM

    Slots are calculated according to VM's Highest CPU and Memory Reservation not according to the allocated RAM and CPU. So if after the slots calculation a VM needs more resources then can HA assign more slots to that VM?



  • 2.  RE: One VM how many slots?

    Posted Jul 11, 2013 05:09 PM

    Note: Discussion successfully moved from VMware ESXi 5 to Availability: HA & FT



  • 3.  RE: One VM how many slots?

    Posted Jul 11, 2013 05:13 PM

    HA won't power off already powered on VM's. However, if the used slots exceed the number of available slots, no more VM's can be powered on.

    Btw. HA doesn't assign slots to VMs, it only calculates the used slots based on the VM's memory settings.

    André



  • 4.  RE: One VM how many slots?

    Posted Jul 11, 2013 05:14 PM

    This should answer your question  HA and Slot sizes - Yellow Bricks



  • 5.  RE: One VM how many slots?

    Broadcom Employee
    Posted Jul 14, 2013 04:09 AM

    RanjnaAggarwal wrote:

    Slots are calculated according to VM's Highest CPU and Memory Reservation not according to the allocated RAM and CPU. So if after the slots calculation a VM needs more resources then can HA assign more slots to that VM?

    As you state: slots are calculated according to highest CPU and memory reservations... so if a VM needs more resources then that has got nothing to do with a slot. A slot is static, demand and entitlement are dynamic. HA does not use those values.



  • 6.  RE: One VM how many slots?

    Posted Jul 22, 2013 05:26 PM

    Thanks Duncan for your reply but suppose if we have 10 available slots then we can start only 10 vm's but if those 10 vm's need resources more than 10 slots then how vm's are getting those resources?



  • 7.  RE: One VM how many slots?
    Best Answer

    Broadcom Employee
    Posted Jul 22, 2013 05:34 PM

    RanjnaAggarwal wrote:

    Thanks Duncan for your reply but suppose if we have 10 available slots then we can start only 10 vm's but if those 10 vm's need resources more than 10 slots then how vm's are getting those resources?

    As stated, resource management (used / demand / entitlement) has got absolutely nothing to do with HA Admission Control. HA Admission Control is about guaranteeing the ability to restart a VM in the case of a failure. CPU / Memory scheduling is something done by the host which is outside of what HA does. HA Admission Control is static. VM resource management is dynamic. So when you have powered on 10 VMs and they need more resources above their slotsize they can and probably will get this assigned based on the consumption of resources on that host, that shares etc.



  • 8.  RE: One VM how many slots?

    Posted Jul 22, 2013 05:49 PM

    thanks duncan :smileyhappy: