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  • 1.  Clustersize / Hosts in cluster

    Posted Sep 19, 2012 06:25 AM

    Hello hello ....appologize if this post is in the wrong section ...:smileyplain:

    Am looking for some best practice information about clustersizes?!?

    Meaning if it is better to have clusters with less or more hosts in it.:smileyconfused:

    Are there some useful links / documents out there? :smileyhappy:

    Am currently have two clusters ( 1st with 3 hosts and 2nd with 6 hosts )

    At the moment I did seperate them simply because servers in the cluster with 3 hosts have newer CPU features.

    ( Which would not be available if I put all in one cluster, but not really have any applications which really benefit of these anyway ... )

    Thanks for info! :smileyhappy:

    ... ah yeah, am on vSphere 5.0.0 build 623860



  • 2.  RE: Clustersize / Hosts in cluster

    Posted Sep 19, 2012 01:07 PM

    Hi  vmarco0815

    Welcome to communites .

    If you don't mind could you please explain the current cluster config little bit more and application running on it .

    "Nature always wears the colors of the spirit."


  • 3.  RE: Clustersize / Hosts in cluster

    Posted Sep 19, 2012 01:11 PM

    Check out this post form Duncan:

    http://www.yellow-bricks.com/2012/04/10/cluster-sizes-vsphere-5-style/

    Regards,

    Mario



  • 4.  RE: Clustersize / Hosts in cluster

    Posted Sep 20, 2012 05:11 AM

    Thanks for feedback already :smileyhappy: ... here is some more information ...

    datacentre:

    cluster A:

    cluster B:

    Anything else which would be helpful to decide if it is besser to have cluster A and B as they are or have all hosts in one single cluster? :smileyconfused:

    cheers



  • 5.  RE: Clustersize / Hosts in cluster

    Posted Sep 20, 2012 05:19 AM

    the HA link from vmario was what I was thinking about.

    another reason to have 2 clusters is maybe you only want to expose only 1 cluster to a dmz.

    if the only reason is evc and you arent using the advanced features, then stick with 1 cluster.

    you dont have that many hosts anyway.



  • 6.  RE: Clustersize / Hosts in cluster
    Best Answer

    Posted Sep 20, 2012 07:15 AM

    I guess there are a couple of things to comment on here:

    • Is there a large discrepancy in terms of resources per host between these two clusters?
      • If No --> go ahead make one cluster and forget about those new CPU instructions, hardly any app will use them / benefit
      • If Yes --> hey this might get tricky from an "admission control" perspective as you will need to take the biggest host into account when it comes to "failures". Now doesn't need to be a problem of course, and you still lose less resources then with 2 clusters
    • What about the infrastructure? All located in the same building? Attached so the same storage? This would drive some of the design considerations around it...
    • Bigger is better for vSphere DRS --> more balancing opportunities

    Typically, I feel that most environments would benefit from 1 large cluster... if you compare it to the benefit they would have from not using EVC I think it is neglectable. go big!



  • 7.  RE: Clustersize / Hosts in cluster

    Posted Sep 21, 2012 01:21 AM

    oh cool - thanks heaps for the feedback! :smileyhappy:

    It's already very helpful!

    In terms of infrastructure are both the same. Located in the same physical datacenter, attached to the same storage and networks.

    Am not sure if discrepancy in terms of resources is large or small. I'd say it's small, but my experience is pretty much just based on this environment, so it might be considered as big? :smileyconfused:

    Maybe the hosts information might help? :smileyhappy:

    hosts cluster A:

    HA advanced runtime info cluster A

    hosts cluster B

    HA advanced runtime info cluster B



  • 8.  RE: Clustersize / Hosts in cluster

    Posted Sep 21, 2012 01:31 AM

    Can't seem to open your screenshots. Are you using rack servers or blades?