ESXi

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  • 1.  DataCenter - Cluster - Resource Pool

    Posted Apr 24, 2012 08:29 AM

    Dear all,

    I am the middle of the design of a vmware platform.

    Situation now: 70 virtual machines running on 1 Datacenter, 1 Cluster. 1 Resource pool created for testing with limited resources. All running on 8 ESX servers.

    I need to implement a new platform and extend virtual machines with another 10 mostly database servers running on another 8 ESX Servers.

    Database virtual servers will be hosted on dedicated RAID10 iSCSi solution, all other machine will be hosted on RAID50 iSCSI Solution.

    Any suggestions about clusters and resource pools?

    Can I add the new 8 ESX Servers in the existing cluster and still only use one resource pool? (easy management)

    Is it better to create a new cluster especially for the database servers? (separation of functionalities)

    Can I vmotion between clusters? (important for initial migration)

    Is it better to create a new resource pool especially for the database servers?

    Any advice really appreciated.

    Kind regards,

    Kenny



  • 2.  RE: DataCenter - Cluster - Resource Pool

    Posted Apr 24, 2012 02:26 PM

    Can I add the new 8 ESX Servers in the existing cluster and still only use one resource pool? (easy management)

    Yes of course! (Are all hosts the same / have the same CPU family?)

    Is it better to create a new cluster especially for the database servers? (separation of functionalities)

    Thats not a requirement, but there could be some reasons, why this would make sence. For example to save licensing costs (especially Oracle).

    Can I vmotion between clusters? (important for initial migration)

    You can´t use vMotion between clusters, but you can disconnect a host from a cluster (while VMs are running) and add it to another cluster. If you have done that you can move the VM to other hosts via vMotion (of course all hosts must have access to the datastore, where the VM is located). Please note, that durring the "disconnect and connect process" your VMs are not protected via HA.

    Is it better to create a new resource pool especially for the database servers?

    This totaly depends on your needs! If your database server are much more important to you as all other VMs you should create a seperate ressource pool, to make sure that in case of ressource contention the DB VMs gets priorized. But watch out to keep the VM to share ratio correct.


    Regards,

    Mario



  • 3.  RE: DataCenter - Cluster - Resource Pool

    Posted Apr 24, 2012 02:35 PM

    Thanks for the answer.

    I don't understand why licensing is involved with cluster setup, but don't think this is relevant here.

    If vmotion is not an option between clusters and there are no good reasons to configure 2 clusters or more than one resource pool, I guess the easiest way is to present all ISCSI storages to all 16 ESX servers and spread vm's over all hosts / storages, working with one cluster.

    All vm's are important because this is only production enviroment, so I guess the best way not to use resource pools.

    Kind regards,

    Kenny



  • 4.  RE: DataCenter - Cluster - Resource Pool

    Posted Apr 24, 2012 02:40 PM

    Still not sure about Vmotion between clusters ... other people say it can be  done

    http://communities.vmware.com/thread/104849



  • 5.  RE: DataCenter - Cluster - Resource Pool

    Posted Apr 24, 2012 02:48 PM

    Sorry I mixed this, with the szenario, where you have 2 clusters, sitting each below its own vCenter (linked mode etc.).

    Probably because I was just migrating 200 VMs between two datacenters :smileyhappy:

    You can use vMotion between 2 clusters if you meet all requirements. This means your clusters need to be below the same datacenter, must have the same LUNs connected and all the other "normal" vMotion requirements (like same vSwitches etc.).

    Regards,

    Mario



  • 6.  RE: DataCenter - Cluster - Resource Pool

    Posted Apr 24, 2012 02:50 PM

    As long as the clusters are in the same datacenter group in vcenter you will be able to vmotion between the hosts - as long as the requirements  for vmotion are met - compatible cpus, communctation between vmotion ports etc -

    a couple of points -

    why do you have a single resource pool under your cluster - it is not really necessary since the cluster itself itself is in essence a resource pool

    I would think twice of putting all of the database vms in the same cluster - the philosophy behind virtualization is putting non-homogenous loads across you environment so that resources can be shared - by putting all database servers in a single clusteer you run the risk of over staurating disk i/o and cpu load because they apply a aimilar type of load where if you can mix in other loads - web servers, file servers application server etc your have a better probability to spread the load - so I would create a single cluster and use resource pools to insure proper delivery of resources - initially only setting resource shares on the resource pools -



  • 7.  RE: DataCenter - Cluster - Resource Pool

    Posted Apr 24, 2012 03:13 PM

    @weinstein5:

    I totaly agree with you that especially disk i/o should be allocated really thoughtfully to DB VMs. But why do I need a seperate cluster for this usecase? With one cluster I am still able to make sure that the DB VMs gets may its own LUNs etc. Also features like SIOC / Datastore Cluster affinity rules etc. can be helpfully with that.

    The second cluster would require a second failover host and limt the flexibility to spread the load (in comparison with bigger clusters).

    Regards,

    Mario