Additional Virtualization Discussions

VDI Sizer and reliability of gold images



1. I looking for a VDI sizer in order to find which FAS could be suitable for a VDI configuration. I read on this community that it exists, but where to download it ?

I know the disk size and the number of IO/s is a key entry.

I'm looking for a tool to evaluate the needs for an office automation usage.

Reading the netapp WP tr-3724, it's seems that for 1000 users, one need of a 3170.

But I read there that a FAS 2050 could be enough

2. Gold images :

Are they reliable if each user have his own personnalized VM ?

I don't like the gold image idea. For me, it's good for a lab, for limited time VMs. But for production, with time, VMs will diverge from the gold image more and more.

Is it possible to update the gold image ? So apply a Service Pack one time for 10 000 desktop VM ? Or do I need to apply the SP to all VMs ?

Thanks .




Hi Marc,

Take a look at this thread on VDI sizing considerations. As you said, it depends on both the capacity and performance requirements

The VDI sizing tool is available here:

Here is a video on VDI sizing:

The tool that can be used to analyze the existing system for IOPS requirements can be found here:

Also, take a look at the new joint VMware/NetApp/CISCO Reference Architecture guide available on both NetApp and VMware sites, highlighting use of NetApp and VMware cloning capabilities to meet requirements for different user types in any environment.

Regarding the gold image / clones, many customers are using them to host 1000s of virtual desktops in production environment. They are reliable for personalized VMs and you only need space for the new writes, discounting the regular dedupe savings you will get. Regarding the patching and upgrading, if the desktops are personalized and users store data on the C drive, you'll have to patch each desktop individually. Othewise, if the desktops are not very personalized and the user data is on the CIFS share, you can upgrade the gold and redeploy VMs.

Hope this helps.





Thanks a lot for this answer.

As far as I read, a FAS 2050 and NFS can be used reasonably for VDI deployment under 500 VDI seats. Is it right ?

With more than 500 VDI seats, one have to choose a FAS with a PAM, so a FAS 3170.

In your opinion, how many 1Gb ethernet link should be configured on the FAS to handle the trafic for 250 users ? 500 users ?

In the sizer, it implies the use of a gold image. Is it mandatory for VDI ?

I think the cache hit rate should be similar with a gold image + dedup and a simple deduplicated volume using DOT 7.3.1. Are you agree with me ?


Best regards


With 4-8 IOPS per desktop, you could use the FAS2050 for 1000 desktops. But definitely use the NetApp tools to do the environment analysis and determine the IOPS numbers for the customer. We have a joint Ref Arch with VMware that highlights the 1000 desktop scenario. Although this Ref Arch was 100% VMware Linked Clones, the architecture is also valid for NetApp FlexCone or mixed FlexClone/Linked Clone scenario.

Also FAS3170 is not a requirement for above 1000 desktops. Although TR3770 used FAS3170 for 2000 desktops, the architecture could easily be supported on a FAS3140 with 2 PAM cards.

Check out page 6 of the document above, we had 2 GigE links per filer on a FAS2050 for 500 users per filer and didn’t see any issues.

No the golden image is not mandatory for VDI. You could use VMware full cloning method. If you create the VMs using VMware full cloning, you would have to buy the storage upfront to create 500 full clones (or e.g. create 100 and then dedupe and then another create another 100 and so on…), adding to the cost, complexity and overall time required to provision VMs, specially if you plan to manage the VMs in a connection broker.




Thanks for theses answer.

Unfortunatly, I have not enough time to stats the workstation because everything should be in production at the beginning of next month . So I can use only the rule of the thumb !

My customer is very concerned by costs (I work in automotive environment).

It happens that the customer prefer Citrix XenServer to support VMs instead of Vmware

And there will be

- only 100 VM as private images. XenServer will use NFS storage on filer as on Vmware.

- 100 VM as shared images. This image will be fully loaded in the RAM of the Windows 2008 PVS server (so no read access to the filer), and 3 Go / VM writable (empty 3Go vhd) for cache.

BTW, I think, I could choose a FAS 2020 in this case. A FAS 2050 is too much expensive. (I work in automotive environment !)