Virtualization over the WAN


If you're like most enterprises, you're either investing or seriously considering investing in virtualization to consolidate your resources. At the same time, you're also looking to spread your work force across larger geographic regions as a way to stay close to your customers.


Unfortunately, those two conflicting goals are wreaking havoc on your wide-area network, which is why so much attention is being paid to WAN optimization technologies of late. After all, if adding more bandwidth isn't cost-effective, how about installing a few appliances to improve WAN performance by, say, 1,000 percent.


Now, it seems the WAN-optimization industry wants to do more than just boost performance. It is looking to extend virtualization capabilities over the WAN to give remote employees the same experience that those at headquarters enjoy.


It makes a lot of sense, considering the increased reliance on remote operations these days. The Aberdeen Group reports that 62 percent of servers and 65 percent of enterprise applications have been centralized over the past few years, even while more than half of all workers are now based outside of company headquarters, a figure that is expected to increase another 7 percent by the end of the year.


Setting up WAN-friendly virtualization schemes takes more than simply boosting your optimization capabilities, although that is a major consideration, according to Silver Peak Systems' Jeff Aaron. You'll also need to prioritize your applications to give the most critical ones preference, and possibly rethink how things like compression and encryption are handled, perhaps relegating these to the optimization device to free up CPU cycles on host machines.


Silver Peak recently helped out a law firm called Linklaters in this fashion. The company had seen some major WAN degradation after deploying a Citrix XenApp virtual desktop architecture across more than 30 locations around the world. Deduping Citrix traffic proved to be a problem due to the platform's low-latency requirements, but with encryption and compression deactivated on the Citrix servers, the Silver Peak system was able to reduce sessions from 7 GB down to about 3 GB, freeing up enough space to improve VoIP quality as well.


Your choice of storage networking also has a major impact on how well virtualization does on the WAN, according to RELDATA CEO David Hubbard. An iSCSI SAN can be replicated over the wide area with no additional gateways or other network components. And while packet loss can increase with distance, this can be easily mitigated through WAN or TCP/IP optimization, both of which will have little effect on Fibre Channel over IP networks.


After consolidation, the biggest benefit to virtualization is network flexibility. The ability to launch multiple operating systems on the same server is a tremendous boon to enterprise productivity. Extending that capability to all employees will only increase their effectiveness.