Question with Clustering

[NateC16]

Hey guys hopefully this is the right spot for this. Anyway, I'm fairly new to this vmware stuff and i was hoping someone could point me in the right direction.

So we are starting to move our servers to virtual machines. And I know we aren't using it to the fullest potential so I figured i'd ask a few questions.

Now I think i understand the "clustering" term, and tell me if im wrong, but from what i get from all of it is that clustering is basically connecting all of the hosts together. More or less..I'm sure there's more technical things along w/ it but.

But the main thing im wondering is if this is possible or if im going at it the right way.

So we are moving to another building and this is how are servers will look: Or somewhat look

Host 1 - Dell R620	Host 2 - Dell R720	Host 3 - Dell R720	Host 4 - Dell R620
Domain Controller (Primary)	Domain Controller (Secondary)	SCCM	Other
Sharepoint	Lync?	Other	Other
Print Server		Other
License Server 1
License Server 2

2 of these will not be on site, and 2 will.

1) Through vCenter are you able to cluster things that are not in the same building? Im assuming you are, but i'd rather make sure.

2) Also can you cluster servers that aren't the same? like the 4 above.

3) How would we set it up so if a host goes down the servers can get moved without everything going down?

Sorry for so many questions I just want to take advantage of the virtualization and use it to its fullest potential, and rather have people who know a lot more than me help me out.

also if there's any good reading or something that can help alot im game for anything

[ssbkang]

Hi Nate,

Here are the answers to your questions:

     1) Yes, you can create two different clusters and can manage them through vCenter server. The location of the ESXi servers won't matter.

     2) Yes, in a same cluster, you can have different model of servers but I would recommend you to use same models in a cluster.

     3) You can setup HA (High Availability) on a cluster, which will protect the virtual machine if a host goes down (there are quite a bit of reading needed to understand fully on HA).

Feel free to leave a reply if you got more.

Regards,

Steven.

[admin]

Nate,

To elaborate more on your 2nd and 3rd questions;

* Clustering is not just connecting all ESXi hosts together, but its another means to aggregate all the compute,memory and storage  resources together to leverage vSphere features like vMotion, FT, HA, EVC etc.

* Get a brief idea about which VMware feature protects planned and unplanned downtime of your servers here

* vMotion is a feature which ensure high availability of the VMs. But to vMotion  VMs across ESXi hosts there are some prerequisites which needs to be met.

  Refer the <link> for more info.

* To know more about hardware compatibility with VMware products refer <link>.

* Access the product documentation for latest vSphere version here

~dGeorge

[NateC16]

Awesome, thanks guys for the replies, it helps quite a bit. I'll do some reading to make sure I know a little more. But just to make sure

Lets say our servers are like this ( just want to make sure i'm thinking of it right )

R720 ( 2 Servers)                         R620 (2 Servers)

196GB RAM                                96GB RAM         

(8) 600 GB HD                             (6) 600 GB HD

So if i cluster the 2 of each it is basically like one big server right? so for the R720's it can kind of be looked at like 392 GB RAM and like 9.6 TB whereas the R620's would be like 192GB RAM and 7.2TB?

So lets say we throw lync onto one of them, if it requires, lets say for hypothetical purposes, 100gb ram, would it pull 100gb ram because of the cluster? is that how it works?

[weinstein5]

No it will not be 'one big server'  - A VM can only run on a single physical server at a time so it will only be able to access that servers physical resources -

[admin]

A cluster is a group of hosts. But adding hosts into cluster doesn't make it a "one big  server". but when a host is added to a cluster, the host's resources become part of the cluster's resources.

The cluster manages the resources of all hosts within it. Clusters enable the vSphere High Availability (HA) and vSphere Distributed Resource Scheduler (DRS) solutions.

[NateC16]

Ah alright, perfect, well thanks for clearing that up makes a little more sense!

This may be  a little off topic, but are we able to move hosts between hosts with vcenter? or did we need another app for something like that?

[weinstein5]

This may be  a little off topic, but are we able to move hosts between hosts with vcenter? or did we need another app for something like that?

If you mean Virtual Machines between hosts  the answer is yes - you would use vMotion which allows you to move running Virtual Machines between hosts in a virtual center environment - this can also be automated using Distributed Resource Scheduler (DRS) which is another feature that requires vCenter to ensure the VMs are getting enough resources -