After much speculation, VMware announced its View 4.5 product at VMworld 2010 last week. Overall, the product is
a major step up from all previous releases, but can it close the gap between VMware and Citrix?
Changes to VMware View
In View 4.5, VMware made changes to its PC-over-IP (PCoIP) protocol. It improved WAN performance and added certification for smartcard support and Online Certificate Status Protocol (OCSP). The company also added support for virtual printing.
Note: VMware has changed its default port number for PCoIP to 4172, so existing users need to upgrade View Client when they upgrade to View 4.5.
Out of these enhancements, the WAN improvements are key. Some IT pros have been skeptical of PCoIP's suitability for the WAN. To help set expectations for acceptable bandwidth and latency values, VMware has published suggested WAN values. It recommends 200 Kbps to 250 Kbps for each basic office desktop that is not graphically intensive. For users that run 480p video, you should plan for 1 Mbps per simultaneous connection. In addition, you should expect network utilization of around 70%, with a latency of no less than 250 ms.
But the amount of bandwidth or latency is only one factor. The reliability of the network link is also important because network sessions with too many dropped packets will harm the user experience. The effect of bandwidth dipping below 200 Kbps on the user's experience depends on the tasks he or she is performing.
VMware has indicated that PCoIP is unsuitable for narrow-band links in the 10 Kbps-to-50 Kbps range.
VMware has achieved these improvements by introducing network bandwidth-estimation algorithms to the protocol and adding corrections to packets that arrive out of order because of network delays and retransmits. However, more testing needs to done against third-party firewalls and virtual private networks (VPNs) using Juniper, F5 and Cisco equipment.
Furthermore, PCoIP remains incompatible with the security server role in the DMZ. Therefore, you still need to open a VPN session before opening a PCoIP session across the WAN. I believe that VMware will soon roll its vShield product into View since the premium edition supports Secure Sockets Layer (SSL) VPN and a load-balancing feature -- two things that View's connection and security servers lack.
VMware also improved its local mode desktop feature, which was known as offline desktop in the previous release. Unallocated blocks and the Windows page file are no longer transferred to the local machine, and VMware also changed the size of the redo logs. Therefore, when a virtual desktop is first taken offline, you get a complete copy of the desktop, but afterwards only the changes are synched to and from the virtual desktop to View. These deltas have been changed from 128 KB to 4 KB, and a smaller block size means fewer changes need to be made, which should make synching quicker. VMware also added bidirectional compression to the sync process and a de-duplication engine so the same data is only synched once.
But the big new feature at the heart of local-mode desktop is the new View server role, transfer server. This service offloads the process to a dedicated server with its own storage allocation, and it is optimized for the linked clones feature.
However, there is a small gotcha: I run it on Windows Server 2008 R2 64-bit. When created in VMware, it defaults to the LSI Logic SAS controller. The transfer role runs in a virtual machine (VM) and will only work with a LSI Logic Parallel controller. You will need to reinstall Windows manually and select LSI Logic Parallel as you go through the wizard. It's a minor irritation but yet another example of how one VMware default is at odds with another VMware product.
The setup of the transfer server adds SCSI controllers on the fly to the VM, which then allows it to mount the virtual disks that make up the virtual desktops ready for local mode to run. It contains a publishing process for linked-clone desktops.
ABOUT THE AUTHOR:
Mike Laverick is a professional instructor with 15 years of experience in technologies such as Novell, Windows and Citrix. He has also been involved with the VMware community since 2003. Laverick is a VMware forum moderator and member of the London VMware User Group Steering Committee. In addition to teaching, Laverick is the owner and author of the virtualization website and blog RTFM Education, where he publishes free guides and utilities aimed at VMware ESX/VirtualCenter users. In 2009, Laverick received the VMware vExpert award and helped found the Irish and Scottish user groups. Laverick has had books published on VMware Virtual Infrastructure 3, VMware vSphere4 and VMware Site Recovery Manager.