The Riverbed Blog (testing)

A blog in search of a tagline

Macintosh support in RiOS 6.0

Posted by riverbedtest on October 21, 2009

Larry Chaffin's blog ( in Network World highlights Riverbed's optimization for Macintosh as one of the key new features in the upcoming RiOS 6.0 software release.  Although Riverbed is also introducing a number of other significant new features in RiOS 6.0, Larry believes Mac optimization will further separate Riverbed from the competition.  Riverbed is the first and currently the only WAN optimization vendor to announce explicit support for CIFS latency optimization for Mac clients using Leopard OS versions 10.5 and later.

Larry's blog comments are notable because use of Macintosh machines appears to be on the rise.  Apple announced just a few days ago on October 19 sales of 3.05 million Mac machines in their most recent quarter, which is a significant 17 percent year-over-year increase from the same quarter in 2008. 

Why is Riverbed's specially-engineered CIFS optimization for Macintosh important?  Although Mac workstations use the same CIFS protocol that Windows machines use to access files over the network, the actual CIFS implementation in the Leopard OSX operating system has some very significant differences compared to the Windows CIFS implementation.  Specifically, the Macintosh CIFS implementations use oplocks differently, and request different file attributes compared to the Windows CIFS implementation.  Use of a WAN optimization product that fails to recognize these significant differences will result in very slow data transfers for certain file requests, or even worse–risk data corruption in a multi-user environment. 

For these reasons, all Steelhead software releases prior to RiOS 6.0 would only apply data reduction–and not application streamlining–to Macintosh traffic when they recognized it, in order to avoid further slowing it down or potentially risking data corruption.  Riverbed is the only WAN optimization vendor who has announced implementation-specific CIFS optimizations for the Macintosh Leopard (10.5) and Snow Leopard (10.6) operating systems, providing further evidence of Riverbed's product and technology leadership in the WAN optimization market.  With the availability of RiOS 6.0, Macintosh workstations in enterprise networks can now enjoy performance benefits such as those experienced by Riverbed customer ESA (performance graph shown below).


2 Responses to “Macintosh support in RiOS 6.0”

  1. Brian said

    Am I reading this right? It took about 225 secs to move 6.3 mb? Are they on dial-up?

  2. Josh Tseng said

    Hi Brian,
    Yes, before Riverbed, they were getting throughput of about 28kB/sec (kilo-Bytes-per-sec), or about 226kbps. Nearly as slow as dial-up, correct. What you’re seeing is issues caused by CIFS protocol chattiness. You see, the maximum block size you can send using CIFS is about 60KB. That means at a minimum, you will need 6.3MB/60KB or 105 round-trips to send this file.
    Now back some 30-odd years ago when Microsoft invented CIFS, that wasn’t a big deal because most networks were local in distance, and the latency was less than 1ms. But WANs nowadays experience latencies of 50ms, 100ms, or even more. Multiply that by 105 round-trips, and you can see where the delay comes from.
    By the way, Riverbed works great with dial-up or 3G networks too. I regularly use Steelhead Mobile on my Verizon Wireless 3G CDMA card (~200-400kbps), and I regularly get upwards of 50Mbps or more for download speeds.

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