New Thunderbolt RAID iMac: lessons learned

New Thunderbolt RAID iMac: lessons learned

Summary: The Thunderbolt RAID/iMac out of the box experience isn't up to Apple standards. But how is it once the system stands up?

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The Thunderbolt RAID/iMac out of the box experience isn't up to Apple standards. But what happens after the system stands up?

(Read my 1st report for background on some of the issues I talk about here.)

RAM up The standard 4GB of RAM is inadequate for the 3.4GHz Sandy Bridge I7 quad-core. The Mac activity monitor shows that 8 GB should be the minimum - unless you do nothing more taxing than open 1 browser tab and read your mail - and if you want a workstation 16 GB is your sweet spot.

With 16 GB installed - which took me about 10 minutes and doesn't void the warranty - it was a new system. My normal workload uses over 9 GB of physical RAM and swap file size stayed near 0. Once I'm back to video production I expect to use it all.

Update: I'm refering to this specific, top-of-the-line iMac configuration, not Macs in general. My MacBook Air is a real workhorse on 4GB. If you're going to invest $2200 in this iMac, plan on adding at least 4GB or better yet, 12GB of RAM to get all the performance you're paying for. End update.

FCP 7 My problem with Final Cut Pro was more serious than I'd hoped: I had to reinstall the entire suite from 6 DVDs. This knowledge base note explains how to recover from a failed FCP migration to a new system.

System performance I ran Xbench on both the old system and the new iMac. The old system was a quad-core 2.66 GHz Mac Pro with some major upgrades: 300GB 10k Velociraptor drive; 1GB ATI Radeon 5770 graphics card; and 12GB RAM.

The iMac has the standard 1TB hard drive, short-stroked by partitioning, the standard 1 GB AMD Radeon HD 6970M video card, 16GB RAM, and the upgraded BTO 3.4 GHz I7 processor.

The overall Xbench score jumped from 185.51 to 269.65, a solid 45% boost. Transcoding a 2 hour, 4GB video file to H.264 took about 40 minutes - way faster than the old Mac Pro.

Thunderbolt array performance I ran the Blackmagic Design disk speed test a couple of times on the 4 drive Promise Pegasus Thunderbolt RAID 5: once with an empty array and again when it was more than ? full. There was little difference in the results.

Here's the over-third-full results:

The little array can handle full 1080p at maximum color depth and space - for a single user workstation - and more in more common formats. Which means it could support a couple of workstations in a shared storage environment - such as with the soon-to-be-free Xsan 2 cluster file system.

Whether Xsan support for shared Thunderbolt storage will materialize is another question, but the potential is tantalizing. Imagine a couple of quad-core MacBook Pros coming in from the field, plugging into a Thunderbolt array and Xsan cluster, and sharing storage and computes with the rest of the shop. Nice.

The little array would be even faster - and safer (see RAIDfail: don't use RAID 5 on small arrays) - configured as a RAID 0 with frequent backups. I plan to do that once I get the requisite hardware.

Running the numbers Was it worth it? Here's how I look at the math.

The entire kit came ?$3,450 - BTO iMac, Thunderbolt cable, Pegasus array and 16GB RAM - plus tax. I sold my Mac Pro tower for $2k, leaving a net cost of $1450. Since the 27" 2560x1440 display I wanted lists at $1k or more, my net cost for 45% more performance, dual Thunderbolt ports and what I expect will be a long-lived array expandable to 12TB or more is $450.

That's a steal.

The Storage Bits take Lessons learned:

  • Thunderbolt works as advertised: fast and seamless. I plugged my 3rd HD display into the array with no problems.
  • The latest iMacs need at least 8GB RAM to function anywhere near their potential - and 16GB is better. Luckily, non-Apple RAM is about $10/GB.
  • Surprised at how hot the iMac runs: 135 degrees F at idle. Increased fan speeds with SMCfancontrol and now it is much cooler and slightly noisier.
  • While Promise has done an admirable job on the management interface, RAID arrays are complex and non-intuitive. If you use the array as configured from the factory it is a simple plug, wait and play process. Otherwise non-sysadmins will face a steep learning curve.
  • The set-up time for a workstation-class iMac is longer than a standard iMac. Allow a day or 2 to get fully configured, data transferred and everything else configured to your liking.

Much of my long-term satisfaction with this buy depends on how Thunderbolt evolves. If it flops I won't have the I/O options I'd like - or they'll be expensive. But after the initial surprises - see yesterday's report - I'm pleased today.

Comments welcome, of course. I'll continue reporting on Thunderbolt and my experiences using it here.

Topics: Processors, Hardware, Storage

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30 comments
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  • I'm really surprised by the RAM requirements

    8GB minimum and 16GB recommended for OS X? Wow. I know that OS X has gotten bloated over the years but that is ridiculous!
    toddybottom
    • RE: New Thunderbolt RAID iMac: lessons learned

      @toddybottom For a "workstation" that is doing video editing then 16GB does not seem to far beyond the pale. Snow Leopard works fine on 2GB on a Core Duo 2 laptop... my daughters for example, but then that is not doing a lot of demand activity like what Robin is doing for a business.
      Jim888
      • I'm going based on Robin's report

        @Jim888
        "The Mac activity monitor shows that 8 GB should be the minimum - unless you do nothing more taxing than open 1 browser tab and read your mail"

        4GB is only acceptable if you open 1 browser tab and read your mail? Like I said, I had heard that OS X had gotten very bloated but wow, I didn't realize it had gotten this bad.
        toddybottom
    • RE: New Thunderbolt RAID iMac: lessons learned

      @toddybottom

      What you don't realize is, a lot of Mac users work with creative technologies, such as video/audio production, 3D modeling, production, rendering and animation, photo editing, etc. These type of processes benefit the most when sufficient RAM is installed. If you're just using MS Word and Excel and perusing the Internet, 4 GB's of memorg is very adequate.
      gtdworak
      • RE: New Thunderbolt RAID iMac: lessons learned

        @gtdworak
        I understand that but Robin is suggesting that 4GB is only suitable if you are opening 1 tab and checking mail. That was surprising to me but Robin is a respected OS X user, I don't think he would be wrong about that.
        toddybottom
      • RE: New Thunderbolt RAID iMac: lessons learned

        @toddybottom

        Don't read too much into one man's experiences .. even a respected technologist like Robin.

        OS X works fine in 2 to 4 GB range on laptops and iMacs for normal activities that you cited.

        However, with RAM prices as low as they are, the old adage, the more RAM, the better is a trusted chestnut worth following.
        kenosha77a
      • RE: New Thunderbolt RAID iMac: lessons learned

        @kenosha7777 [i]However, with RAM prices as low as they are, the old adage, the more RAM, the better is a trusted chestnut worth following.[/i]
        Oh, brings me back to the "good old days" spending $1,500 on a 128 MB RAM upgrade because 3D Studio Max was chocking my system when rendering :-(
        non-biased
    • RE: New Thunderbolt RAID iMac: lessons learned

      @toddybottom

      Did you read the article b4 making inflammatory assaults?

      4GB is great for OS X on most systems.

      I have often used 256mb Macs running OS X and outperforming Windows with 1GB.

      512MB is a good working amount for decent OS X use. 1GB is great.

      So - no OS X is not bloated at all.

      Sorry - no points for your spin assault.
      richardw66
      • Of course I read the article

        @richardw66 <br>Did you read my post? I'm surprised that it was confusing.<br><br>Regardless, I'm impressed that you were able to get Snow Leopard running with only 256MB of RAM. Apple lists 1GB as the minimum. I'm also trying to think if Apple ever sold a 256MB RAM Intel Mac. Not positive but I would be surprised if they ever did.<br><br>And what does Windows have to do with this?<br><br>Sorry that you felt it was a "spin assault" (I can only guess at what you mean by this but it doesn't sound good). I was merely expressing my surprise at Robin's statements.
        toddybottom
      • RE: New Thunderbolt RAID iMac: lessons learned

        @richardw66 :

        Bull54!t. I needed to upgrade my MBP from 4GB to 8GB doing nothing more than standard engineering work, nothing near as taxing as what Robin is doing.
        brichter
      • RE: New Thunderbolt RAID iMac: lessons learned

        @brichter Yet I have absolutely no problems working in Photoshop, Premiere Pro and After Effects all at the same time on my MBP with 4GB.
        non-biased
  • Funny, I'm fine here

    on a Macbook with 4GB. And I usually have a lot going on. It's a no brainer if you have heavy needs you need heavy RAM.
    itguy10
    • RE: New Thunderbolt RAID iMac: lessons learned

      @itguy10 My MBA with 4GB is fine too, for the SSD makes page swaps almost invisible.

      One of the issues is, no doubt, the fact that I have over 8 million pixels in my 3 displays, so I keep a lot of windows open. I think there's also an issue that with more CPU cycles one needs more RAM to feed it - unless you're idling along.
      Robin Harris
      • RE: New Thunderbolt RAID iMac: lessons learned

        @Robin Harris

        I hope you don't let your SSD handle the page swaps... SSD's only have limited amount of reads and writes they can handle over a lifetime so if you wear it out too fast because you have low memory and are constantly doing page swaps you're going to be buying a new hard drive sooner than expected.
        FormalForker
      • RE: New Thunderbolt RAID iMac: lessons learned

        @Robin Harris You're probably not swapping much then... Or atleast your definition of invisible is different from mine. Even swapping on an SSD is 600MB/s vs. 8000MB/s for DDR2-1066. The math doesn't indicate invisible for a high intensity application. <br><br>Plus, it's fairly hard to waste 4GB of ram unless you're doing something fairly intense like running a java enterprise server + oracle or photoshopping a 20 layer image.
        snoop0x7b
      • RE: New Thunderbolt RAID iMac: lessons learned

        @FormalForker

        I am sure he will be long gone by the time that happens. New SSD have long life spans, and the larger the drive, the longer the life. It's not an issue.
        Tiredofdumbasses
      • RE: New Thunderbolt RAID iMac: lessons learned

        @Robin Harris :

        Robin already said his swap size is near zero...
        brichter
      • RE: New Thunderbolt RAID iMac: lessons learned

        @Robin Harris There is no relationship between CPU cycles / cores and the amount of memory required to "feed it". You could peg all cores with code executing in the cache alone (optimal for speed). Conversely you could have an enormous amount of memory allocated and have very little CPU activity. It simply depends on the # of applications running and their memory requirements. If you had 32 cores at 5 Ghz you should be able to do normal computing easily with 2G of ram regardless of OS (less with Linux). But who wants to do normal computing on such a system if it existed? :). You do utilize memory more efficiently (generally) with 32 bits vs 64 bits so that is a factor.
        DevGuy_z
  • Memory

    I just put 8GB into a new 17" macbook pro. The statement that you need 8GB for "nothing more taxing than open 1 browser tab and read your mail", isn't quite true. If you use Aperture, you'll want it. Final Cut X, will want it. I was fine doing audio production with Logic on 4GB AND 10 tabs of chrome, iTunes and some other nonsense running. But for $100 you can get the 8GB - so why the heck not?!
    samgreene
  • RE: New Thunderbolt RAID iMac: lessons learned

    16GB? Yep. Lesson learned, alright: Don't buy one. Sheesh.
    ttaz4dqm