2 Replies Latest reply: Jan 8, 2010 9:03 PM by Michael Card
Michael Card Level 1 Level 1 (110 points)

I am setting up a testbed with an Xserve (Snow Leopard Server) and a 16 TB VTrak disk array. I have a few questions:

(1) Can I set up XSAN2 without a Standby Metadata Controller (MDC)? I only have 1 Xserve, not 2, so I would like to forego the redundancy for now.

(2) If I use my Xserve as a Primary MDC, will I be able to run applications on it? My hope here was to run multi-threaded apps that would take advantage of all 8 cores and be able to access the VTrak array in parallel from each core and still get fast access.

(3) Would I be better off using my VTrak as DAS? Teh problem it seems to me with DAS vs NAS is that if you have parallel acces (multiple threads running on multiple cores accessing the same files) you get I/O bottlenecked, was hoping to get better performance from the SAN.

Thanks for any thoughts you have on this and any guidance!


Xserve, Mac OS X (10.6.1), XSAN 2
  • 1. Re: New to Xserve/XSAN deployment question
    Mark Raudonis Level 1 Level 1 (70 points)

    By the nature of your questions it sounds like you're trying to "cheap out" on X-SAN. This is a recipe for disaster. An X-SAN requires a minimal level of dedicated resources that you seem unwilling to commit to. Perhaps this is NOT the solution for you. There are other "SAN IN A CAN" solutions out there that may better match your budget.

  • 2. Re: New to Xserve/XSAN deployment question
    Michael Card Level 1 Level 1 (110 points)

    What are the "SAN IN A CAN" alternatives you refer to here? Do you have any links/product names you can refer me to?

    Why is it a recipe for disaster? What do you mean here by "disaster"? Suboptimal performance?

    What we want to do is get concurrent access from multiple threads running on multiple cores in our Xserve to the VTrak without having the threads "bottleneck" at the disk. Maybe running the VTrak in the DAS configuration is better, perhaps X-SAN really only helps when you have multiple Xserves as "clients" in the SAN.

    Certainly we had not budgeted for 2 Xserves to be used as MDCs and needing to buy a 3rd to actually run our application.

    Is there anyone reading this thread who could tell me what the performance of 1 Xserve running a 16 TB VTrak as a DAS would be vs. an Xserve client accessing the VTrak over XSan? Perhaps Xsan really only "buys you something" when you have multiple Xserves hooked into the SAN but it really doesn't buy you anything when you just have multiple cores accessing the SAN from 1 Xserve...