Mindmap for Horizon View Storage Design Considerations
I have come up with mindmap which explains what are various considerations and dependency in calculating VDI storage requirements. Please note it is in DRAFT and will continue to be updated as when I learn about storage. I’m using MindMaple product for mindmapping. I found it very easy to use and customize. Above all it is free to use. In the mind map below there are three major considerations for VDI Storage.
At first glance you might not see much but as I expand the map further you might feel it is making sense. Let’s start with IOPS first.
In IOPS we start with Types of application and number of application. E.g. If the application is graphics heavy it will need more IOPS. If application is a video recorder it would need more write IOPS. So we need to know what is the Read/Write ratio of these applications? Windows XP, Windows7, Window8 and Windows10 will differ in terms of IOPS requirements. All these parameters will influence RAID type which will further impact number of disks. IOPS will also get influenced by User profiles as shown with dotted arrow and it is most relevant when we don’t know IOPS requirement of applications which is generally the case.
In tier type, we might have to decide on whether to select SAS disk or SATA disk. Please note typical VDI Desktop is made of three different disk types
Linked Clone Disk
Persistent Disk (User Data Disk)
Disposable Disk (temp and page file)
Linked clone disk might go on 15K/10K disk based on the application requirement e.g. for Autocad you will definitely need 15K disks. Therefore tiering will definitely have some inputs for IOPS. Similarly user profiles will drive persistent disks, non-persistent disks which will further influence IOPS.
Storage capacity has significant number of considerations and all are coming from desktop size. Desktop size needs decision on persistent desktop/non-persistent desktops. There is best practices maximum on number of VMs you can put per Datastore as per Ray’s blog. In non-persistent desktop your refresh interval drives the size. If you are refresh desktop at user logoff, then normal Linked clone size growth is consider only 10% of replica disk. Further, configured memory and reservation will have impact on Swap file and therefore on storage sizing. If you are looking for 3D support for your desktop, additional Swap file is created which will again impact the disk size. How much disk space you are considering for desktops. OS Type selection will also have impact on desktop size as memory and CPU requirement varies as per OS type which is shown using dotted arrow.After your desktop size is finalized, multiple that with number of desktops for storage capacity, add overhead which is normally 10% of total storage requirement. Using max VMs per Datastore you can calculate number of LUN size and size of each LUN.
Hope this helps you and I will continue with mindmaps in future blog posts