How does VDI work?
Is All-Flash required, or can it work on other storage arrays?
No, you don't need allflash - but it depends how many users. If you deploy 'desktop just in time' then all vdi instances are in RAM (with small footprint on the storage). Allflash is recommended but not required. It's recommended to have separate storage for VDI solution. Look at vmware.com site - they have great documents and videos how it works.
VDI uses a server solution for virtual desktops. This way the horsepower needed to run applications comes from the server-side and not the client-side.
This enables a couple of main things: a similar desktop experience for the end-user no matter where they are and what hardware they are using, and cost savings on the hardware required for the end-user. It enables patching and security benefits as well. The drawbacks are bandwidth requirements and server infrastructure cost. Using an all-flash storage array would help in the IO limitations of the server because any storage requests would be fulfilled quickly.
Pros: consistency in all desktops (they are all the same), speed and performance, patching and security, easier upgrades, lower desktop machine cost, server maintenance.
Cons: high server hardware requirements, server storage cost is higher, need a higher bandwidth between server and desktop, server maintenance.
Any kind of decision to use VDI needs to consider the cost benefit. Would using a virtual desktop be worth it? You decide.
VDI is a server farm for virtualizing dedicated user desktops. Detailed information can be found at this link, for example, VMware https://www.vmware.com/topics/glossary/content/virtual-desktop-infrastructure-vdi
How does VDI work?
In the case of my organization for 2 thousand. 20 TB data has been reserved. VDI solutions have a large data reduction (deduplication and compression, up to 20: 1). If the data is reproducible, this factor may be even higher.
Is All-Flash required or can it work on other memory arrays?
VDI can work on hybrid arrays, but they are not so efficient in boot storm, non-Vistist, VDI, reboot of the whole farm, low response times below 1ms, requirements of similar experiments as on PC.
Very good question, but a world is opened when speaking about VDI. I think that flexibility and ready to use are the most importat aspects. All-Flash in not required but it depends on the answer you get to "what should VDI use for"?
Do you mean Virtual Desktop Infrastructure? If so, then it has no relation to flash storage. VDI can work on any storage. But it will be faster using flash storage.
I don´t think that the answer for this - very general question - what vdi is, is that simple! Of course you can always give answers by definition makes on Wikipedia, or from companies which are selling vdi-solutions. But the mainpoint, in my opinion, is always the perspective of the asking person. vdi can be the simple virtualization of clientsystems - but vdi can also be the "hardcore" virtualization of extreme workstation, clientsystems, or just something between, something with application streaming etc. etc.
So it is not that simple to answer the first question. And … than out of this the result for the second question is not that simple either. Of course all of us can say - nothing is better for displacement then get more displacement. So of course you can slay al kinds of workloads with the power of all-flash - but is it every time necassery? I don´t think so. Is it every time economic? I don´t think so. So first of all - talk much more precise to your customer and try to reach his painpoints, so you can decide if VDI is really necessary, and how you have to design a new storage implementation to fit the conditions of the customer best.
Regarding VDI solution, Yes you have to get a full flash storage solution because you will have high IO, need high bandwidth, for a small capacity. Only flash storage responses time has the right solution.