steverdavidson
Contributor
Contributor

Unclear on number of hosts allowed

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Here is a blurb from the vCloud Architecture Toolkit v 3.0

Each NewCo provider virtual datacenter corresponds to one and only one vSphere HA/DRS cluster. While a vSphere 5 cluster can scale to 32 hosts, typically 8–12 is a good starting point that allows for future growth. The recommendation is to start with eight hosts in a cluster and add hosts to the cluster as dictated by customer consumption and utilization metrics such as when utilization reaches ~60%. In a provider virtual datacenter that leverages the fast provisioning feature and iSCSI or Fibre Channel based storage, the vSphere cluster size backing a provider virtual datacenter is limited to eight nodes. Through the concept of pooled and abstracted infrastructure, capacity can be added to the vCloud through this method allowing for expansion of provider virtual datacenters and the corresponding clusters without impacting running vApps. If expanding an existing cluster is not an option, VMware recommends that a new provider virtual datacenter and corresponding cluster be deployed.

I was happyto see that I could have up to 32 hosts.

Then I read that if I use Fibre Channel based storage (which I will) the cluster size backing a provider virtual datacenter is limited to eight nodes.

Hmm.  Back to 8 hosts?

I read on:

Through the concept of pooled and abstracted infrastructure, capacity  can be added to the vCloud through this method allowing for expansion of  provider virtual datacenters and the corresponding clusters without  impacting running vApps.

So I am thinking maybe the limit is NOT 8?  Confused, because they say that using pooled and abstracted infrastructure, capacity can be added...

Soo. What is the limit for number of hosts in a vSphere cluster size?

🙂

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mreferre
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I have just got confirmed it's a typo. It will be updated in the next release cycle of the doc.

Thanks!

Massimo Re Ferre' VMware vCloud Architect twitter.com/mreferre www.it20.info

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charliejllewell
Enthusiast
Enthusiast

Hi Steve,

A tricky one but I am not sure there is a definitive answer as it depends of limitation on the features you wish to use. For example in vCloud 1.5.x the cluster limitation is 8 hosts if you wish to use fast provisioning and VMFS whereas the limit is 32 hosts if you wish to use fast provisioning with NFS. The best advice I can give is to keep reading the docs. Work out what features you must have/what features you would like and then work out what the limitations of each feature are based on your infrastructure requirements.

Hope this helps and sorry its not a clear cut answer,

Charlie

mreferre
Champion
Champion

I was under the impression that the 8 hosts limitations for Fast Provisioning on VMFS was improved with 5.1.

Perhaps a refuse in the text of the doc (we have used part of the previous versions of the docs where it made sense).

I am checking with the other doc owners (I didn't personally work on that part). 

Massimo Re Ferre' VMware vCloud Architect twitter.com/mreferre www.it20.info
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mreferre
Champion
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I have just got confirmed it's a typo. It will be updated in the next release cycle of the doc.

Thanks!

Massimo Re Ferre' VMware vCloud Architect twitter.com/mreferre www.it20.info
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steverdavidson
Contributor
Contributor

So the limit is NOT 8 with fast provisioning and san storage?

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tsugliani
VMware Employee
VMware Employee

If i'm not wrong the correct answer is (for Fast Provisionning & FC/iSCSI) :

if vSphere & ESXi = 5.1 then the limit is now 32 (it has been improved in this release specifically)

if vSphere & ESXi < 5.1 then the limit is 8

Hope this makes sense ?

steverdavidson
Contributor
Contributor

excellent.  thanks!

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charliejllewell
Enthusiast
Enthusiast

Good to know, thanks Smiley Happy

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vwade
Enthusiast
Enthusiast

Timo is correct, the 8 host limitiaon has been lifted for fast provisioning as long as you adhere to the following requirements: you are using VCD 5.1, your provider VDC is backed by vSphere 5.1, and you are using VMFS5 datastores. What vCAT document and section was the typo in?

Wade Holmes | VCDX #15 | Senior Solutions Architect  |  twitter @wholmes

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steverdavidson
Contributor
Contributor

it is in the private vmware vcloud implementaton example.pdf

search for Each Newco or go to page 34.

Perhaps there is a newer version of this document?

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