Citrix? XenDesktop 4 VDI

[oxide54]

Anyone know how to download the eval of XenDesktop VDI edition?

seems they only let you download the express edition, trouble is i can't really evaluate the provisioning and other hypervisors with that version?

any one?

[wrights]

Sorry to bounce an old thread but hopefully it will help when you come back after the Christmas break.

If you create a "MyCitrix" account (www.mycitrix.com), login, select "Product Previews / Beta releases - License Retrieval", and choose "XenDesktop Evaluation" from the drop down list you'll get a trial licence.
After you have a trial licence your "MyCitrix" area will allow you to download XenDesktop - I think the trial is for Enterprise but if you don't deploy XenApp it's very similar.

For most setups you would be better to look at Enterprise; a deployment of XenApp will allow you to stream applications into the XenDesktop VDIs so you don't have to maintain a collection of applications in each VDI, it will also allow you to publish a shared copy of commonly used software that runs on central servers thereby decreasing VDI resource requirements and making maintenance much easier.

[oxide54]

hello mate,

all it was, was it looked like a service pack rather than the full release. it was called "service pack 2." coming from the microsoft school of thought ( dangerous I know! ) i was presuming it was the service pack 2 rather than "xendesktop 4 with service pack 2 applied" !

I have since trialled xendesktop and been very pleased. I love provisioning server, its amazing what you can do with it. the only concern I have is hardware driving the IOPS for large scale deployment.

[wrights]

Multiple PVS (Provision Services) servers can run on the same subnet to allow for failover, when you do this they need shared storage to prevent both PVS servers having to have copies of the VM disks that are being provided.
It is quite normal to use two Windows servers with a standard CIFS repository and data (the VM disks) duplicated between the Windows servers using DFSv2, thus the PVS servers don't actually have any real IOPS load.

The IOPS load on the Windows servers is read heavy, and as the servers are ideally dedicated and do little other than provide the VM disks the frequency of disk hits can be reduced by increasing system ram available as a disk cache.
PVS will also allow you to cache data on the VM (great if you are booting on physical hardware rather than VMs, or deploying XenApp) and to separate the temporary file location (which is write heavy) from the data store used for VM disks (which is read heavy).

Believe it or not you don't actually need a lot of hardware for a large scale deployment, the key really is to keep the number of VM disks in use to a minimum and ensure ram is available to decrease hits to the disk.

I haven't tried it yet but Sun's ZFS L2ARC technology should really help PVS and further reduce disk requirements.

[oxide54]

i can see you don't need much when deploying to physical to machines, but surely when using vm's the write cache will cripple a san if your not carefull?

[wrights]

You'll get about 50 VMs running on just 8 disks if the write cache IO actually hits the drives, using something like ZFS L2ARC technology should allow the IO to take place on a solid state disk which allows massively more IOPS and hence substantially decreases the number of normal drives required.

The solid state disk wouldn't need to be very large, we'd normally be deleting the write cache when a user logs out.