Add Seamless Scalability, High Availability and Simplified Storage Management to Citrix Virtual Solutions with Sanbolic Melio 2010
Hi, my name is Andy Melmed and I am the Director of Enterprise Solutions for Sanbolic Inc., a developer of software products designed to simplify, share and extend the capabilities of SAN storage.
As a new guest blogger on the Citrix Community blogs, I plan to use this forum to explain how Citrix ISVs, VARs and customers around the globe are enhancing Citrix virtual solutions with virtual shared storage provided by Sanbolic. In my blogs, I’ll cover a wide range of topics that focus on using our software to improve the scalability, availability, flexibility and manageability of Citrix virtual solutions, including new product features, configuration best practices and recommendations, infrastructure design options, etc. I will also include references to newly published white papers and configuration papers to make sure you have the latest information on how Sanbolic is helping organizations realize the greatest return on their investments in Citrix technologies.
For my first posting, I’m going to explain how Sanbolic’s flagship product, Melio 2010, enhances Citrix XenDesktop virtual desktop and XenApp application delivery infrastructures powered by Citrix Provisioning Services (aka PVS). To begin, I’d like to pose the following questions:
Are you currently in the planning and design phases of deploying a virtual desktop and/or application delivery infrastructure using XenDesktop and/or XenApp?
Are you planning to take advantage of the performance, scalability and reliability capabilities of SAN storage to store the virtual images (vDisks) that will be streamed to virtual machines hosting desktops and XenApp servers?
Are you spending a lot of time looking for the best way to ensure these infrastructures achieve the highest levels of performance, scalability, availability and manageability in order to realize the greatest return on your investment?
If you answered “yes” to one or more of the above questions, I strongly recommend taking a few minutes to read the following white paper: http://www.sanbolic.com/pdfs/HA_Options_for_Citrix_Virtual_Solutions.pdf.
This paper highlights the storage options most frequently considered by organizations looking to enable high availability for Provisioning Services (the underlying technology used to stream desktop and server OS images on demand to virtual machines hosting virtual desktops and XenApp servers).
Once you’ve finished reading the paper it will be obvious why, out of all the options available for enabling high availability for Provisioning Services, only Sanbolic Melio 2010 actually enhances Citrix XenDesktop and XenApp!
The following diagram illustrates how Sanbolic Melio 2010 integrates into a XenDesktop virtual desktop infrastructure:
Organizations that have deployed XenDesktop and XenApp with Sanbolic Melio 2010 have achieved the following:
1. Simplified maintenance of vDisk images by consolidating all vDisks onto a single volume on SAN storage, with all vDisk changes available for streaming by multiple PVS Servers immediately, i.e., no need to replicate the vDisks to different PVS Servers to ensure vDisk version consistency.
2. Enhanced I/O performance using stripe sets (comprised of disks from multiple storage arrays) that leverage multiple storage controllers, caching and spindles to improve the user experience.
3. Quick and seamless scale-out by adding more PVS Servers or more storage resources on the fly, with little effort and no interruption to user productivity.
4. Reduced storage costs through greater utilization of storage resources.
5. Centralized management of storage resources as all physical disks are virtualized and managed from a single console that can be accessed locally or remotely.
6. Improved fault-tolerance via high availability of PVS vDisks and databases.
7. Enhanced vDisk protection with cluster-wide or individual vDisk snapshots.
Compatible with all industry-standard server and storage hardware, Sanbolic Melio 2010 runs on Windows Server operating systems, allowing multiple PVS Servers to share concurrent read-and-write access to a single volume on SAN storage that contains the vDisks and optionally, device write cache files. This configuration enables high availability of PVS vDisks to ensure maximum uptime for virtual desktops and XenApp servers as well as high availability of PVS databases, enhancing system fault-tolerance.
For mid- to large-size XenDesktop and/or XenApp infrastructures, only highly scalable and highly available shared storage provided by Sanbolic Melio 2010 and SAN storage offers the levels of performance, scalability, flexibility and manageability necessary to meet both current and future demands while allowing organizations to achieve the greatest return on their investments in these industry-leading solutions.
If your interest in Sanbolic Melio 2010 is piqued by the information presented in the white paper and you’d like to see a live demonstration that shows how Melio 2010 enhances Citrix virtual solutions, please contact Sanbolic at sales@sanbolic.com and one of our sales representatives would be happy to schedule a demonstration for you.
For a more detailed look at how Sanbolic Melio 2010 enhances Citrix XenDesktop, check out http://www.sanbolic.com/pdfs/Optimizing_Citrix_XenDesktop_VDI_Solutions_with_Sanbolic_Melio_2010.pdf, which explains how Melio 2010 enables the seamless scale-out of XenDesktop to allow organizations to extend the benefits of VDI to a larger percentage of their users.
To learn more about Sanbolic’s SAN-storage enhancing software, please visit http://www.sanbolic.com. We’re confident you’ll see why Melio 2010 is the ideal choice for enhancing Citrix XenDesktop and XenApp virtual solutions. And while you’re there, check out all the other solutions we enhance, such as scalable file and web-serving farms, highly available SQL Server clusters, and enterprise-class server virtualization with Microsoft Hyper-V.
Sanbolic… Building better solutions with virtual shared storage!
Notice: The views expressed in this blog belong to Sanbolic, Inc. and have not been authorized by Citrix Systems, nor do they necessarily reflect the views of Citrix Systems.
Choosing a thin client OS for your desktop virtualization deployment can be tricky. Windows embedded thin clients offer the latest features, but they cost more and have additional security implications and maintenance compared to Linux based thin clients. Wyse ThinOS clients are often easier to secure and manage than Linux clients, but often lag in features. This has changed with the use of the Wyse TCX software, but because of the “thin” nature of ThinOS a few key features are not possible. Let’s take a look at the latest features available when using the latest Citrix clients.
| Feature | Windows XPe |
Linux | Wyse ThinOS with TCX | Comments |
|---|---|---|---|---|
| Flash Redirection | Yes | No | No | Wyse ThinOS with TCX supports flash acceleration which is not as desirable as flash redirection. |
| Multimedia Redirection | Yes | Yes | Yes | All clients support multimedia redirection for video codecs such as wmv, mpeg and avi. |
| USB Remoting | Yes | Yes | Yes | All clients support isochronous USB remoting such as Webcams and offer USB PDA sycronization. Wyse ThinOS utilizes the TCX software. |
| VOIP – Optimized Speech codec | Yes | Yes | No | XPe and Linux client support the new Citrix speech codec. Wyse ThinOS uses TCX Rich Sound which is less desirable. |
| WAN - Branch Repeater Client | Yes | No | No | Only XPe clients support the Branch Repeater Client, but the Linux client supports HDX IntelliCache WAN Optimization. Wyse has a Virtual Desktop Accelerator for software WAN acceleration. |
| HDX 3D Graphics | Yes | Yes | No | The Linux client does not support decoding of GPU-compressed data streams. |
Common features across the thin client operating systems include support for multiple monitors, bi-directional audio, USB flash drives and web browser acceleration. Many of the Wyse TCX features work out of band which means they will not work with Citrix Secure Gateway or a Citrix Access Gateway running in Secure Gateway mode.
For more information you can read this white paper on selecting thin clients for XenDesktop 4.
You can also check out this Wyse software pdf file on Wyse TCX and other Wyse software.
Sunil Kumar
Principal Architect, Desktop Virtualization
CSC Consulting
Most people know by now that XenDesktop supports three virtualization platforms with VMware ESX being one of them. However, there are at least four different editions for ESX. Even if you have decided to use ESX for all or part of the XenDesktop deployment, which edition do you really need? Can you stick with 3.5, or should you use 4.0? As part of the CSC Dynamic Desktop offering, we have researched what virtualization features are useful in a XenDesktop deployment and here are the results.
Before I continue further, I want emphasis that I am focusing on which version and edition is needed to host the XenDesktop virtual desktop VMs. The XenDesktop server infrastructure components such as the DDC, XenApp and Web Interface should follow the same policy as your other server VMs. Since server and desktop VM requirements differ quite a bit, it can make sense to use one virtualization platform for servers and a different one for desktops.
Since your virtual desktop VMs have different requirements, what ESX features are beneficial in a XenDesktop environment? The following is a list of those features with a brief description of their functionality and what ESX edition is required. Except where listed, each feature is available in both ESX 3.5 and 4.0.
| Feature | ESX Edition |
| PXE / Boot ISO Support - The Provisioning Services component in XenDesktop communicates with the virtual desktop VMs during boot via PXE or a boot ISO. | Standard |
| XP & Windows 7 Support - Support for running Windows XP and Windows 7 VMs. | Standard |
| Memory Ballooning - This allows for free memory in each virtual desktop VM to be used in other VMs and the ESX host using a balloon driver run in the VM. This feature is useful in cases where extra capacity is needed such as when another ESX host fails. | Standard |
| Transparent Page Sharing - This is another memory saving feature that identifies duplicate memory pages across VMs on the host and only stores a single copy. This consumes extra CPU cycles to identify the duplicate pages but this is adjustable. Depending on your needs you may not want to use this feature. | Standard |
| vStorage Thin Provisioning - With thin provisioning you only need storage for what data is being used rather than the actual formatted capacity. This works well for the PVS write back cache when the storage device does not support thin provisioning. | Standard (4.0 only) |
| High Availability - This feature is useful in an assigned XenDesktop environment where each user is assigned their own virtual desktop VM. If the ESX host running their virtual desktop goes down, their desktop would be restarted on another host. | Standard |
| vMotion - This features allows an administrator to manually move a running VM from one ESX host to another host which usually has less load. This requires that the hard disks for each VM are located on shared storage. | Advanced |
| Dynamic Resource Scheduler (DRS) - DRS dynamically allocates and balances the virtual desktop VMs across a resource pool. This feature basically automates the vMotion feature listed above. | Enterprise |
In summary most of the features are available in ESX Standard which retails for around $1590 for a dual-socket server. Paying an extra $2900 gives an administrator the ability to manually rebalance VMs across the ESX hosts via vMotion and an extra $4160 (compared to standard) provides automatic load balancing of VMs. Taking a ballpark conservative estimate of 50 users for the latest dual-socket server the cost per user is about $32 retail per user for ESX standard, $90 for ESX Advanced and $115 for ESX Enterprise.
The next logical question is if it is worth an extra $83 per user to be able to dynamically load balancing running virtual desktop VMs across ESX hosts? In some cases it will be, but for most cases if you need to use ESX in a XenDesktop deployment, ESX Standard is the better choice. The additional thin provisioning functionality in 4.0 does not usually justify an upgrade from 3.5 especially if this functionality is supported in your storage device.
If you are using XD with ESX, what version and edition are you using? Are there any other features that you find useful for managing your virtual desktop VMs? Feel free to leave a comment or you can contact me via email.
Sunil Kumar
Principal Architect, Desktop Virtualization
CSC Consulting
There are several pros and cons when choosing between blade or rack servers related to power consumption, consolidated networking, manageability and cost. These comparisons are readily available over the Internet, but what makes one preferable to the other in a XenDesktop deployment? Let’s take a look at a few of the differences.
Higher Density XenServer Resource Pools
Rack servers offer more quad-socket models compared to blades and also offer greater memory capacity and the latest processors. This translates into higher VM density per server which is important because the size of a XenServer resource pool is limited by the number of XenServer hosts and not by the number of VMs. So by using quad-socket rack servers you can have a greater number of virtual desktop VMs per XenServer resource pool. In a large XenDesktop environment this means fewer resource pools to manage.
Advantage: Rack Servers
Isolated OS Streaming Traffic
Streaming the OS from the PVS host to the virtual desktop VMs can take significant network bandwidth especially when the virtual desktops are booting. This OS streaming traffic can be isolated per blade chassis. Each VM server would use the PVS host located in the same blade chassis but could failover to alternate PVS hosts in another chassis if needed. Setting up an isolated network with rack servers is possible but is much more complex.
Advantage: Blades
Lower Storage Costs and Faster Performance
Each virtual desktop VM needs a cache to temporarily store the “writes” while streaming a PVS standard image. Depending on your environment this could require 1GB to 5GB or more of storage per virtual desktop VM but could also be used for storing EdgeSight user performance data or any persistent data such as anti-virus definition files. Fast RAID storage options with local hard disks are possible with rack servers which is important because local storage is much less expensive than SAN storage even when using thin provisioning on the SAN. Having this write back cache located on the same server will usually be faster and easier to configure rather than putting all the write back caches on the SAN. One downside is that dynamic load balancing of the running virtual desktop VMs is not available since the storage for the virtual desktops are local to the VM server.
Advantage: Rack Servers
Summary
In conclusion both choices offer benefits in a XenDesktop environment. I personally prefer rack servers because of their ability to use several local hard disks. Keep in mind that your choices for network switches and network storage could significantly swing your decision one way or the other. If you have any questions please feel free to leave a comment or email me.
