The Mission:

Upgrade three XenServer 5.0.2 hosts in a single Pool with an iSCSI attached Storage Array to the new and improved XenServer 5.5.

The Process:

The first thing we did was install the XenCenter 5.5 Client and, just to be sure, went on to apply the 5.0.3 update (aka update 3) to all of the hosts. After that it requires a reboot (of course). To facilitate this, we were glad we had multiple hosts in the same pool as we were now able to utilize the ever popular XenMotion to ‘shuffle’ my VMs around, reboot a host, ‘shuffle’ the VMs again, reboot the next host, etc.  This worked like a charm.

After we completed Update 3, we then cleared off the Primary Host (denoted by being the top-most Host of the Pool in XenCenter) using XenMotion.  Using a browser (IE needed unfortunately – alternative with FireFox is IETab Plugin) we connected to each of the HP iLOs from our management server (physical windows host), mounted the XenServer 5.5 Disc 1 in the iLO virtual DVD-ROM drive and rebooted the physical XenServer host. The iLO also equips you with an ActiveX remote KVM for just this purpose, thankfully.  We proceeded with the XenServer installation and even installed the Linux Pack (second ISO image… dismount the XenServer ISO and then mount the Linux Pack ISO all from the Virtual Drive functions in the iLO).  Once the primary is completed, here is a catch: if you XenMotion/Launch a VM on 5.5, you CANNOT migrate it off to an older version host so plan carefully. That being said, we XenMotioned our VMs around several times (yes this does hurt performance on the VMs if you are overloading your hosts… see Noticable Issues) and completed all of the upgrades.

Now that all of the Hosts were done and our VMs were still running, we scheduled outage windows for each set of subsystems to allow us time to upgrade the XenTools on each VM (all 31 of them… yes 31 VMs on 3 hosts).  No, there is not a way currently to mass update all VMs, so you have to do them one at a time.  Watch out here too… see Noticable Issues.

All in all it wasn’t a horrific upgrade process, thankfully we have an excellent team that works well together under pressure.

Proof Positive – XenMotion keeps VMs accessible:

To provide proof positive that I was able to keep Citrix XenApp sessions running while doing this all, I logged into our HostMyIT (Hosted Messaging and Collaboration / Virtual Office) system prior to any work.  My session stayed running throughout the entire process using Outlook 2007 as a published application.  However, new logins eventually stopped… see Noticable Issues for an explaination.

Noticeable issues:

1. One of our Windows Active Directory Servers lost connection to our NetApp SAN (we use CIFS for the file shares) and this caused file access denials.  The simple solution (after wracking our brains) was to redo the NetApp CIFS Setup routine.  Instant access restored.

2. XenTools updates: Caused one of our iSCSI LUNS (used for Exchange’s Database) to be overmapped by the XenServer VCD-ROM.  We had to  remap the CD-ROM drive letter to J:, reconnect the iSCSI LUN to the Exchange Server and map its drive letter back to D:.  Chances are, you will only hit this one if you use iSCSI LUNS mapped to lower drive letters.

3. Overloading your Physical Hosts with too many VMs will be seen by users as a noticable slow down occurs.  Let your users know several thousand times prior to upgrade if you will be doing this while live.

If you are considering/planning a XenServer upgrade, let DedicatedIT be your Team, give us a call (561.491.5725) or drop us a line.

The issues enclosed in this post are just the ones we ran into in this specific upgrade.  There are always snags.  As I said before, it’s not a horrific upgrade process, but it is nice to have that same great team by your side that we do internally.

Application virtualization is typically used to describe a product that packages applications into network-accessible objects and delivers them to client (or terminal server) operating systems capable of executing the application locally inside of an isolation environment (in order to limit dependency on the underlying OS). Such products include Citrix Application Streaming (a feature of XenApp aka Presentation Server), Microsoft App-V (aka SoftGrid), and VMware ThinApp. Each of them are designed mostly with the same result in mind, though each product has its own ‘quirks’.

Client Application Delivery Methods

Methods of delivering client applications (whether directly installed or virtual) include ‘thick’ clients (local execution), terminal services, VDI or blade computing. Thus, the term ‘application delivery’ relates to how users receive or gain access to their applications.

These technologies (application virtualization and application delivery) are complimentary, not exclusive, and successful solutions typically incorporate more than one product or methodology.

That said, each of the three major application virtualization products have their own benefits, typically related to licensing expenses and the bundling of such products with other solutions already in place. Business drivers and technology initiatives make up the rest of the equation.

Microsoft Desktop Optimization Pack from App-V

For instance, an organization who acquires all of their desktop licensing through a Microsoft volume program and also acquires the Desktop Optimization Pack receives use privileges for App-V. Unless this particular organization is under a mandate for SBC, they aren’t tossing out their desktops and as such will utilize the features they have already paid for. Conversely, organizations using XenApp with enterprise or platinum CALs receive usage rights for Citrix Application Streaming and wouldn’t have a need to purchase App-V for TS.

Citrix Application Streaming using XenApp

Citrix has put forth large efforts to incorporate multiple delivery methods into a single consistent interface for users. Application Streaming can be performed directly to desktops or indirectly through a XenApp presentation session using the same web-accessible interface (and the intelligence for ‘dual-mode’ streaming is centralized in the farm to prevent the user from having to figure it out). No one else has accomplished that type of integration yet.

DedicatedIT: Virtualization Experts for Miami to Palm Beach

Virtualization and desktop delivery are specialties within specialties. Make sure your South Florida virtualization consultant has experience in addition to certifications.

Are You Sure?

If you can’t answer ‘yes’ without hesitation, call us today: 561-491-5725.

Network Monitoring, Data Backup and Server Security

DedicatedIt provides around-the-clock network monitoring, complete system backups as well as Windows sever security and patching. We have trained and certified analysts that will make sure your Microsoft servers, Cisco routers, Citrix farms and NetApp SANs are all operating securely and efficiently.

24/7 System Monitoring Less Expensive than Crash or Data Theft

For $50 a month, your business can have its Microsoft Windows server under our protection. This service includes:

• Aggressive, complete monitoring, 24-hours per day, 365-days per year
• Problems fixed (restart services, patch troubleshooting, disk space cleanups)
• Secure, remote access to server
• Proactive Windows server security patch management

If your server was out of service for just one day, it would cost you more than a year’s worth of monitoring, maintenance and prevention. Downtime is very expensive and greatly impacts a business.

Contact DedicatedIT today to learn more about our Windows server monitoring and patching service for Miami, Palm Beach and South Florida businesses.

We are often asked about the differences in graphics performance between VMware View and XenDesktop. Summary: XenDesktop has better performance than VMware View.

RDP for Terminal Services vs ICA for XenApp

Those running RDP for Terminal Services and ICA for XenApp (formerly Citrix Presentation Server) side by side, can guess which product delivers better video graphics performance. Anyone who has done a comparison will have seen the performance difference. Delivering virtual desktops to remote users requires excellent performance for a seamless user experience. ICA has clear advantages over over RDP.

Third-Party VMware View VDI Accelerators vs Native XenDesktop

Yes, there are third-party products for VMware View VDI delivery and graphics acceleration, but now you’re adding additional expense and complexity. XenDesktop provides the same capability or better in a single product, with a single license and a single cost. Some third-party VMware View products even require the use of specific client hardware. That defeats the goal of dynamic infrastructure doesn’t it? Having to rely on specific hardware as a client isn’t exactly “anytime, anywhere” delivery in practice.

Video Comparison of RDP and ICA for Desktop Delivery

Below are side-by-side RDP and ICA HDX demonstration videos that show which VDI product has the best desktop delivery performance.

Please contact DedicatedIT today, 561-491-5725, if you are interested in learning more about Citrix XenDesktop or other desktop virtualization solutions for your business.

While most transitions to XenServer 5.5 are proceeding seamlessly, there are a few snags being encountered by the bleeding-edge adopters. Contact DedicatedIT today, 561-491-5725, with questions and concerns about your XenServer 5.5 Upgrade.

XenServer 5.5 VDI Sizes

Citrix has always been straightforward about their supported limit of a maximum 2TB size for a single VDI.  However, previously to 5.5, it was possible to create larger LVM-based VDIs.  Users that have upgraded to 5.5 have discovered that they are no longer able to mount those huge VDIs to their VMs.  Citrix has its highest-level engineers on it, but Citrites aren’t promising anything yet.

‘SR Backend Failed’ Errors

Another problem relates to VMs not being able to start after the pool upgrade is complete – XenCenter returns:

The SR backend failed to complete the operation.

Resolutions do not appear to be consistent at this moment.  Some are successful by just forgetting and attaching the SR, while other users find success by refreshing the 5.5 install on the pool master.

Guest Network Performance Problems

Some users have reported a big drop in guest network performance after updating Xen Tools on the guests.  So far, the only resolution has been to uninstall the Tools package.

VM Snapshot Considerations

Many users are making the early jump to 5.5 in order to have the ability to create snapshots of any VM on any SR type.  The downside to this is that your VDIs will be converted to VHD. This will have an impact on performance because a filesystem is being introduced to the SR – how much of an impact is yet to be determined. Additionally, VHD files have a hard 2TB limit. Also, creating the snapshot requires an amount of freespace equal to the size of the VDIs being snapped. It appears that the privileged domain isn’t creating a delta file but instead replicating the base file.

As we discover more, we’ll add them here. Also, if you’ve had any ‘fun’ experiences upgrading to 5.5 in your shop, let us know!

Cheers,
~Phil

“Base installation repository was not found at that location. Please check and try again.“

We’ve seen this one come across a few times, especially with virtual media mounts (DRACs moreso than others). The install routine is probing the wrong storage device paths looking for the installation image on the CD or ISO.

How To Fix XenServer Base Install Repository Error

Jump over to vty1 (ALT + F2) and execute the following command:

modprobe ide-generic

Jump back to vty0 (ALT + F1) and the next media search should find the installation image successfully.

Need XenServer Install Support? Call Us: 561-491-5725

As always, please let us know if you found this helpful! Or, if you are stuck and need help, please contact DedicatedIT for XenServer installation help.

~Phil