Instant Clone Desktop Balancing Across Datastores

[MarkNLH]

Quick question on how desktops are balanced across multiple datastores. We are going to eventually bring our POC to production and will need to provision around 400 desktops. We envision that we will have 6 datastores with 2TB of SAN space for each datastore to house these 400+ desktops. My question is how will Horizon View manage the storage and the balance across these 6 datastores if I was to just provision 400 desktops all at once? Would they automatically be spread out or is there a manual process that I would need to follow to make sure proper balance is achieved?

Let me know if you any details and thanks for the help!

Regards,

Mark

[angelage1]

Horizon will automatically rebalance across the datastores so you wouldn't have to worry about that.  One thing I do want to point out is that you should minimize the number of datastores you deploy for your instant clones.  For every datastore, instant clone creates a replica VM (which is a full clone) which is used for internal management purposes, so if you have a 50GB image, and you are using 6 datastores, you will incur 300GB of space just for the replica VM.  Since you only have 400 desktops, why not just provision them in 1 or two datastores? 

[MarkNLH]

Thanks for the fast response and information, Angela. Do you have any links to any reference articles or best practices for this phase of our build and deployment? I believe our thought was to have more datastores in case of failure so we wouldn't lose all of our production desktops.

[angelage1]

We don't have anything specific on the datastore design of instant clone.  Here's one that is higher level https://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/techpaper/vmware-horizon-view-inst...

[angelage1]

One other thing, since instant clones are stateless desktops, if you lose a production desktop because the datastore has gone down, Horizon will simply create another one in another available datastore. 

[MarkNLH]

We have an all flash array san, is there a size limit to the datastores? If we went with only 2 datastores they could end up being around 15-20TBs each.

[sjesse]

If these are instant clones, which don't clone the full disk size, I don't think you need that much space.? Instant clones, link linked clones, are just a delta off parent image. I don't have a large horizon enviornment, our biggest desktop pool has 87 instant clones in its own data store right now, these are based off a 60GB image. I'm using 1.46 TB for 87 instant clones, which is about 17GB per instant clones. Saying these are similar to yours, which may or not be the case, I would assume 400 would be 7TB. Maximum Lun size per

https://www.vmware.com/pdf/vsphere6/r60/vsphere-60-configuration-maximums.pdf

is 64TB for fiber channel, with 2048 powered vms per volume. According to the horizon sizing guide

VMware Knowledge Base

they don't mention space, just to keep the number of VMs below 500 to ensure each vm has enough iops.