Bounty 100 rep coming: I know I'm asking a lot here and I'd like a detailed/quality answer so, as soon as I am able, I'll be adding a 100 rep bounty to this question.

I'm trying to illustrate the problem of this setup to my superiors but I'm not a professional system administrator; So, I figured I'd ask the pro sysadmin community for some backup on this one.

The configuration consists of:

  • 3 Promise Pegasus R6 configured as Raid 50 arrays chained via a Thunderbolt (copper) interface
  • A Mac Mini server running as a dedicated file server
  • A Cisco 4900M Catalyst switch (don't ask ::sigh::)
  • 3 iMac Workstations
  • 2 Dell Laptop Workstations
  • 3 Xerox Production Printers

Here's a little background. The workstations are dedicated to professional graphic design and video editing and the storage array's primary purpose is to act as a data repository for the workstations.

What I'd like to know is, what is the maximum theoretical throughput of the connection from a workstation to the storage array broken down into simple terms (Kilobytes/s Megabytes/s).

Note: Brownie points if you can illustrate a NAS (Network Attached Storage) setup with equal or better throughput.


For those who are curious, the controllers are Promise Pegasus R6. You can find the spec sheet here.

  • Also, if somebody could add the 'thunderbolt' tag, I'd appreciate it. I don't have enough rep on this site to do it myself. – Evan Plaice Jun 28 '12 at 18:02
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    You're kind of looking at the problem through the wrong lens. You're not listing the drive speeds in that array, or telling us how many IOPS are being generated. Those are far more important numbers than either the fact that one of your interconnects is Thunderbolt, or that you have 3 printers. – mfinni Jun 28 '12 at 18:07
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    The maximum is going to be 1 gigabit/s or ~120MB/s since you only have 1 network port. Trying to place several fast storage arrays behind it sounds, to me, like madness. – Zoredache Jun 28 '12 at 18:07
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    @Zoredache And that's assuming no overhead. Common assumptions put that number closer to 100MBps. – Chris S Jun 28 '12 at 18:12
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    Serverfault doesn't generally allow questions asking for shopping recommendations. In any your question is almost completely pointless. Almost nobody uses storage in a way where the maximum bandwidth matters. Seek time, (latency) is what matters. This is expressed as how many operations can be performed per second, and that is directly related to the drive RPMs, and spindle count. As my first comment suggested, the maximum throughput doesn't matter, since you won't be able to use it connected to a mac mini. – Zoredache Jun 28 '12 at 18:33


Based on your response "the interface on the iMacs and laptops will be gigabit (theoretical)" - then, as Zoredache pointed out - your theoretical max is 120MB/s. It'll be lower, as Chris S said, allowing for normal network overhead.

The system is as fast as the slowest NIC. In this instance, that's the gigabit NICs on the workstation. You also don't provide much info about the RAID 50 arrays - what controller, etc. It is possible you'll hit a limiter there as well.

  • Beat me to it! :) – Joel E Salas Jun 28 '12 at 18:20
  • Updated the info. The thunderbolt arrays are Pegasus Promise R6 in a RAID 50 configuration. – Evan Plaice Jun 28 '12 at 18:25
  • The Pegasus Promise R6 doesn't show itself as supporting RAID50. – Zoredache Jun 28 '12 at 18:28
  • @Zoredache Here's the specs store.apple.com/us/product/H5187VC/A/… – Evan Plaice Jun 28 '12 at 18:29
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    And here is the spencs from the Vendors Web site. promise.com/storage/…, which I usually find is more trustworthy then what you can find on the Apple store. – Zoredache Jun 28 '12 at 18:31

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