VDI server/broker design & questions?

[needcaffeine]

\[note: currently managing a cluster of vmware servers - running 50 production VM servers(4 minimal use desktops)]

I've been challenged with creating a secure desktop environment, and I think VDI is my best option.

The VMWare servers/data will reside in Hong Kong and the users will connect via thin clients from mainland China. We'll be using vista, so that we can swap between languages for ease of administration. One or 2 applications will be accessed via a citrix client on the VDI back to the US.

I'd like this system to run with as little admin as possible, but do want to ease any desktop help desk administration as possible.

-Does a the RAID type of a SAN storage truly improve peformance if there is a large cache? or does just max # of heads matter?

-Are you using roaming profiles for your VDIs?

-Can a broker or HA/DRS start a VM if no more VDIs are available?

-In theory does a broker....allow you to set all thin clients to connect to a single location, and then assign a free VDI? Can you set pools of VDIs based on the authenticating user?

Server scaling - were currently running more then 6 VMs per core - but those are servers. I'm looking to have Nx1 2socket Quad core servers, how much VMs per system should I spec assuming 15% load per VM(based on Vista performance issues)?

[mreferre · Accepted solution]

>Does a the RAID type of a SAN storage truly improve peformance if there

>is a large cache? or does just max # of heads matter?

There are debates on this from time to time. I guess it really boils down to your own pattern: if at a given (same) point in time the 100% of your vm's are hammering the disk (i.e. they boot up or do any other things that hammer the C: drive) than perhaps a solid back-end disk subsystem might help ...... For the other major circumstances your VDI back-.end won't hammer the disk so much.

-Are you using roaming profiles for your VDIs?

ROaming profiles are typically used with pools of vm's and you want to provide some sort of end.user personalization.

-Can a broker or HA/DRS start a VM if no more VDIs are available?

See the link below

>-In theory does a broker....allow you to set all thin clients to connect to a

>single location, and then assign a free VDI? Can you set pools of VDIs

>based on the authenticating user?

See the link below

>Server scaling - were currently running more then 6 VMs per core - but

>those are servers. I'm looking to have Nx1 2socket Quad core servers,

>how much VMs per system should I spec assuming 15% load per VM

>(based on Vista performance issues)?

I am not familiar with Vista vm's but most users are reporting some 6-8 VDI vm's per core.

For the other questions and to get more info on VDI deployments I suggest you have a look at both this documents:

http://it20.info/files/3/documentation/entry20.aspx

http://www.it20.info/misc/brokers.htm

HTH.

Massimo.

[needcaffeine]

I had looked as most of those links before, most of the images are distorted, maybe they were were too webified? maybe make them GIF vs jpeg?

I know what roaming profiles do...I tried them back with NT4, not very useful on slow data lines, especially when users can save large data files to their profile, though great for citrix though

for LUNs what type of RAID are most people using 10? 5?

maybe I missed it, but can a broker, autostart a VM if there are none left in a pool?

[admin]

With VDI your mileage is going to be the same with roaming profiles if the profile server and hosted desktops are close to each other. Its the display of the desktop that is being sent across the slow link.

Depending on the link you still need to consider delivering a full desktop and the implications.

A feature rich broker that integrates with with Virtual Center will provision a new vm in a pool if they have all been checked out. It should also support multiple Virtual Centers as well so you can scale out. I also would look for it to offer a suspend / shut down policy. If VM's are idle or unused it cant make more resources available in the cluster. HA if implemented will handle your restarting efforts.

I have seen LUN configurations all over the Map with both iSCSI and SAN.

I am guessing you plan to deploy later? Currently, ESX 3.x only has experimental support for Vista and there are some know issues. Stable for testing and such but not recommended for production till full support is available.

[sgrinker]

maybe I missed it, but can a broker, autostart a VM

if there are none left in a pool?

Yes - If there is a VM provisioned/configured but not currently powered on.

Maybe - If there is no extra VM provisioned currently.

The second option depends on the broker, and not all of them have an "AutoProvision" feature as of yet. Most of them are working on that in some way or another though. I should be fair, in saying that not all have the ability to power on a machine either, but that's much more of a common feature lately.

[mreferre]

>I had looked as most of those links before, most of the images are

>distorted, maybe they were were too webified? maybe make them GIF vs

>jpeg?

Yes they are distorted that's why I published the presentation as well (posting the pictures into a web page didn't make them look good). Sorry about that ... I am a web publisher in the spare time

>I know what roaming profiles do...I tried them back with NT4, not very

>useful on slow data lines, especially when users can save large data files

>to their profile, though great for citrix though

As Warren mentioned roaming profiles won't be travelling through slow links but through the file server and the centralized vm's (thus always at datacenter speeds).

for LUNs what type of RAID are most people using 10? 5?

I would say 5 simply because you (today) need so much space to host your vm's that raid 1 would just be a killer from a price perspective. Others might have different opinions though.

Steve touched on the autostart feature ....

Massimo.

[needcaffeine]

I'm looking to deploy by year end, the vista desktop will be as basic as possible, the only reason to go to vista is for the language change on the fly.

I'm in the midst of the designing the data center (nothing exists currently)

To start we're going to have E1 connections, do you think that an E1 should support 30 VDI connections, plus VOIP?

All but 1 application will be hosted in Hong Kong, and all will be vmware.

[admin]

Well a lot of people tend to disagree with me on this topic. Typically RDP/ICA bandwidth usage is tossed around in averages. Things look better with averages. The typical number tossed around is 25 Kbps per session.

Sure, on average I see my virtual desktop use 25 Kbps but that includes me sleeping as well when my virtual desktop is doing nothing.

I see healthy spikes go above 900 Kbps. You have to account for the peaks and valleys. It will always depend on the applications as well as the profile of the users. For example, a call center agent that is heads down is typically going to use more than a sales guy that is coming and going.

Personally, when I am doing a swag, I like to use 100Kbps - 150Kbps as a rule of thumb. If you were to use that methodology that would be about 14 concurrent users. If I am off by 50% and you do not mind your users suffering a bit when things get tight, your golden

I suspect it takes some time to get a line provisioned in main land China? Last I check while having this same discussion with someone looking to do 1500 desktops an OC3 was going to take six months so you may want to consider that as well in case you agree with my methodology.

[sgrinker]

I suspect it takes some time to get a line

provisioned in main land China?

Yes... it does. Just speaking from 2nd hand experience as our guys just went through the same out there. Definitely make sure to give it enough time.

[needcaffeine]

we've already signed the contract about a few weeks ago, it's estimated at 90 business days.

it's rather disturbing - it's a lot cheaper to get lines in china, then it is to get lines in most of my US locations. (granted I know that we're 7th in the world as far as telcom is concerned)

we're going to go w/ E1s to start, singles in our locations, and bound E1s in our data center.

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needcaffeine