Get your GeekOn w/ RonDesigning your VDI Servers

Not a Unidesk demo, commercial or infomercial. Just pure geekiness.

Agenda

Defining the VMs before designing the serversMemory ConsiderationsCPU: Processor type? Cores over speed?

Video impact?

Storage ConsiderationsConverged systems?Final thoughts

Define/Design your VMs firstNumber of vCPUs

This leads to a discussion about vCPU count and multi-media in Win7, which leads to a discussion about video offload

Memory assigned to the VM Has an impact on disk design

Disk space (define the use case first)Networking requirements (DHCP, reservations, Static)OS and application requirements

CPUs

CPUs where to start?VDI can tax a system CPU differently than you expectThe goal is always to increase density in your VDI

server but don’t trust ‘Vendor numbers’The choice/tradeoff

Optimal config (performance wise) is a low ratio of Virtual Desktops to cores in the server

Optimal config (cost wise) is a high ration of Virtual Desktops to cores in the server…

1- Don’t go “cheap” on the processor2- Trade Cores for Speed

Video’s CPU Impact – its 2 different thingsPCoIP Offload cards

Offloads PCoIP functions from the CPU to this cards Density numbers they quote may only be seen when LOTS of

desktops are using the CPU for PCoIP functions http://www.vmware.com/files/pdf/VMware-View-Using-PCo

IP-HostCards-TN-EN.pdf

NVIDIA VGX GPU cards NVIDIA Quadro GPU http://blogs.vmware.com/euc/2012/05/blog-post-from-gtc-h

osted-desktop-and-workstation-workloads-what-about-my-3d-graphics.html

Common CPU “issues” seen in the fieldOver taxing the servers (number of vCPUs to Cores)

The higher the ratio of vCPUs to physical cores the more time VMs have to ‘wait’ to be scheduled on a processor core

Often indicated by a high % Ready time

In some servers there is a “speed step” issue Speed step or power settings configured in the BIOS is not

allowing full CPU utilization at lower server CPU utilization Has been seen in Cisco, HP and Dell servers Often correctable How do I know if this is happening to me?

Memory

MemoryDefine your memory assignments NOW before you

ever pick your server Often the scale tests you see from vendors are not optimal

configurations for memory This setting impacts way more than just the VM

Memory overcommit tools only allow so much over commit Think about 100 VMs at 4GB each…..

Memory also impacts your storage… HUGELY

Memory and StorageVMware creates a vSWAP file equivalent to the

machines assigned RAM… it does this at each bootA Windows page file MUST be present for Windows to

operate properlyOn a 4gb of memory machine this can equate to 6+ GB

of space eaten up 4GB of vswp + 2GB of page file + other data Imagine that for 1000 desktops… 6+TB of space eaten Or think about it with a 100% pagefile… 8+ TB

Moving to Host Based vSwap?Host based vswp moves away from individual vswp

files stored per VMRequires that you have local storage for this swap

space can also run swap to host cache! http://www.vmware.com/files/pdf/mem_mgmt_perf_vsphere5.pdf http://pubs.vmware.com/vsphere-4-esx-vcenter/index.jsp?topic=/

com.vmware.vsphere.resourcemanagement.doc_41/managing_memory_resources/t_enable_host-local_swap_standalone.html

http://pubs.vmware.com/vsphere-50/topic/com.vmware.vsphere.resmgmt.doc_50/GUID-FE1108F3-C4CF-41F3-AEE9-CDB5B44A444F.html

http://www.yellow-bricks.com/2011/08/18/swap-to-host-cache-aka-swap-to-ssd/

Disk

Disk FootprintFirst you have to decide what the local disk will be

used for: Just ESXi installed? Local host based swap replacing vswap per VM? Local copies of VM replicas or Unidesk Layers?

Define the footprint required for each Hot data (shared layers, VM Gold images, etc) Colder data (vswap, windows page files, Unidesk boot

images, etc) This footprint requirement will feed into disk selection

Disk IO… the common problem.Footprint can be reduced via numerous technologies

IO… not so muchServer IO loads? What is/was typicalDesktop IO loadWhat is all this RAID penalty stuff?

Design for the IO, there are optionsBig storage vendors push the big system with their

“Cache” tech Fast Cache Flash Cache

Regardless of disk TYPE the key is handling IO and the storage footprint at the same time Centralized storage looked for mixed / hybrid arrays with SSD

and rotating disks – make sure they use some SSD for writes Local storage can also be leveraged to keep cost down

Everything is available from rotating disk to FusionIO cards

Local storage options for IOSSD can have its draw backs

Failure rates on consumer level SSD can be an issue for VDI Standard MLC on a hot server… I’d give it a year or 18 months eMLC should be 4 or 5 years SLC 6-8 years? But at generally more than 2 or 3x MLC/eMLC

Or… lots of rotating: 6 drives * 200 IOps can I get 8? 50 desktops at 10 IO each with 1:1 read:write = 1250 IO 1 FusionIO card + 2-4 rotating disk for swap & transient data?

http://www.brianmadden.com/blogs/rubenspruijt/archive/2012/06/10/spinning-out-of-control-using-flash-storage-in-enterprise-environments.aspx

So what about these “converged” systems with servers, storage,

everything?

Converged systems playThe idea is to combine your compute (server) and

storage resources together into scalable appliancesVery cool model, focus on $/desktop and perfromance

Nutanix.com Very cool, redundant storage, 4 server block model

V3 Systems v3sys.com Redundancy through automation

Designing your VDI environment and avoiding common mistakes

Common Mistakes in VDIDesigning the hardware first

To many variables to choose hardware out of the gate; Just duplicating Server Virt hardware

Believing everything the vendors say… Buying software because the “vendor said” it would do what

I needed The vendor said I could get 120 Desktops on this system

Not configuring the Disk subsystem properlyForgetting about “personalization” of the desktop

Hardware RecommendationsSmaller servers w/ more cores

Going to 4 socket boxes from 2 socket is not a simple 2x change in price

More memoryGood storage controllers Local disk, SSD, centralized disk, centralized SSDBuild redundancy through quantityThink back to the old “MetaFrame Days”

Key “Check Boxes” for your designDefine what you are delivering and to whoEnsure your design covers the following:

Base OS delivery and updating Application delivery and updating Personalization or profile mgmt Broker configuration and requirements Pool Vs Persistent desktop decisions Storage configuration (foot print and IO load) WAN and LAN use cases

Q&AOpen Discussion

Ron Oglesbywww.unidesk.com

Twitter: @ronoglesby