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By Henry Baltazar  |  Posted 2006-06-26 Print this article Print
 
 
 
 
 
 
 


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With MAPI (Messaging API) acceleration in place, IT managers no longer have to maintain e-mail servers at each of their remote sites. This not only facilitates storage consolidation but also allows IT managers to implement an e-mail archive at the core data center.

To test MAPI performance with the Riverbed and Blue Coat appliances, we ran a VBScript that launched Microsoft Exchange, sent a message with a 6MB attachment and timed the send transaction.

Running without WAN acceleration, this process took 126.8 seconds.

To read an eWEEK Labs review of Double-Take Application Manager, click here. Riverbeds solution cut down the transaction time to 34.7 seconds with a cold cache and a mere 1.28 seconds with a warm cache. Blue Coats solution provided a significant improvement compared with the nonaccelerated process, but its performance trailed Riverbeds by a fair amount: With a cold cache, Blue Coat finished the transaction in 86.63 seconds; with a warm cache, it took 30.17 seconds.

Replication Tests

In our final test scenario, we used the WAN accelerators in conjunction with Double-Take Softwares Double-Take data replication solution. We turned off Double-Takes built-in compression capabilities to allow the WAN accelerators to work at their full potential.

We set up file servers with Double-Take on both sides of our WAN and created a job that replicated across the WAN a 4GB VMware image of a Red Hat Enterprise Linux server and a file folder containing roughly 600MB of data.

Without WAN acceleration, Double-Take pushed traffic across the WAN at a pedestrian rate of 8MB per minute.

The Blue Coat appliance with a cold cache was able to speed the data delivery rate up to 61MB per minute. For the second run, with a warm cache, Blue Coat accelerated the data transfer to 308MB per minute.

Switching over to Riverbed, we saw a cold cache performance reading of 63MB per minute and a warm cache reading of 488MB per minute.

Sizing Up Expectations

As can be seen by our performance numbers, WAN accelerators can speed up traffic significantly. What cannot be ignored, however, is the sizable performance disparity between warm and cold caches.

IT managers need to do careful data analysis before setting performance expectations. Sites that are constantly sending new data over the WAN will likely see performance improvement on par with our cold cache numbers, while sites that primarily send modified versions of existing files will see performance similar to the warm cache readings.

IT managers need to be mindful of the fact that each WAN accelerator has a set amount of cache. In the case of Riverbeds appliances, caches range from 35GB in the entry-level Steelhead 100 and 200 units all the way up to 512GB in the top-of-the-line Steelhead 5010.

Purchasing an undersized WAN accelerator can lead to erratic performance because the cache will not be able to keep up with user requests.

These products can be deployed relatively easily, so we highly encourage IT managers to test these solutions with their own data before making a buying decision.

Future Considerations

The next major leap for these products will be acceleration of SSL (Secure Sockets Layer) traffic over the WAN. Riverbed and most WAN acceleration products on the market do not have this capability right now, although Blue Coat does.

Leveraging its SSL proxy capabilities, Blue Coats SG800 can intercept and terminate SSL traffic—and then unencrypt and optimize it—before the data goes over the WAN.

Given the sensitive nature of encrypted traffic, we recommend that IT managers perform a thorough security assessment before implementing this type of SSL acceleration.

Next page: Evaluation Shortlist: Related Products.



 
 
 
 
 
 
 
 
 
 
 

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