1 2 Previous Next 18 Replies Latest reply: May 28, 2012 7:12 PM by FatMac>MacPro
Luca (LDF) Level 1 Level 1 (0 points)

Hi everybody!


It has been a while I am using a Netstor external HD (NR710C) 4x2TB WD Caviar black, RAID 10 (4TB total space, 2.71 Available, MacOS Extended Journaled).

It is conntected with the MacPro (MacPro 4,1 - early 2009) via a Sonnet Tempo SATA E2P pci card (drivers updated)

The OS installed is Mac OS X Lion 10.7.3 (11D50d) on a OCZ SSD 250GB


What happen is that randomly the access  to the external RAID HD is very slow and while finder try to open subfolder the entire system freeze for a minute or so. Soemtimes the opened folders looks empty and I have to wait a minute or so to see the content.

When I used Snow Leopard (installed on a 1TB HD) the access was always fluid and fast.


What I've done to try to solve this issue is:

Unchecked the "Put the hard disk(s) to sleep when possible) in the Energy Saver panel.

Changed slot of the PCI card

Changed sata plug and cable

Performed all the check disk possible


It happens as well that the copy/move of big folder (up to 800GB) is not always as fas as it should be.

Also, working with Lightroom (cache is on the SSD hd) is really frustrating due the slow access to all the files.

I was used to work directly on the external sata HD but now seems like if I have to move everything back on an internal HD.


Is there any other check I can perform to address this issue?


So many thanks.



Mac Pro
  • 1. Re: Very slow external sata HD (lion)
    The hatter Level 9 Level 9 (58,885 points)

    Get a card with more than the limits of the E2P which is going to limit your I/O - great for backups and such.


    CallDigit PCIe 6G perhaps - I'd say Sonnet E4P but cost and issues sometimes with Lion.


    Also,  can I assume this worked with 10.6.8 better but not with Lion and new driver.

  • 2. Re: Very slow external sata HD (lion)
    Luca (LDF) Level 1 Level 1 (0 points)

    Thank you!

    I will have a try before to buy new HDs.

  • 3. Re: Very slow external sata HD (lion)
    The hatter Level 9 Level 9 (58,885 points)

    The case has one SATA to eSATA cable?


    will be limited by the controller interface and E2P

    that it has its own RAID bridge

    and is port multiplier type drive enclosure


    Direct connect 4-port SATA or a higher performance PCIe SATA card would really be req'd

  • 4. Re: Very slow external sata HD (lion)
    Luca (LDF) Level 1 Level 1 (0 points)

    The case has an eSata port and cable.


    I've run a speed test (Xbench) on a 2TB internal drive and the external RAID.

    Here is the result. It seems the speed is good.. is it correct?


    System Info

    Xbench Version

    System Version
    10.7.3 (11D50d)

    Physical RAM
    16384 MB


    Drive Type
    WDC WD2001FASS-00W2B0

    Disk Test98.66


    Uncached Write212.82130.67 MB/sec [4K blocks]

    Uncached Write181.19102.52 MB/sec [256K blocks]

    Uncached Read123.1636.04 MB/sec [4K blocks]

    Uncached Read227.40114.29 MB/sec [256K blocks]


    Uncached Write21.962.33 MB/sec [4K blocks]

    Uncached Write441.42141.31 MB/sec [256K blocks]

    Uncached Read155.381.10 MB/sec [4K blocks]

    Uncached Read242.8645.06 MB/sec [256K blocks]


    System Info

    Xbench Version

    System Version
    10.7.3 (11D50d)

    Physical RAM
    16384 MB


    Drive Type
    Netstor H/W RAID10

    Disk Test97.50


    Uncached Write182.92112.31 MB/sec [4K blocks]

    Uncached Write144.6281.83 MB/sec [256K blocks]

    Uncached Read104.6330.62 MB/sec [4K blocks]

    Uncached Read216.80108.96 MB/sec [256K blocks]


    Uncached Write22.292.36 MB/sec [4K blocks]

    Uncached Write205.8865.91 MB/sec [256K blocks]

    Uncached Read360.622.56 MB/sec [4K blocks]

    Uncached Read332.3761.67 MB/sec [256K blocks]
  • 5. Re: Very slow external sata HD (lion)
    Ricks ricks@macgurus.com Level 6 Level 6 (11,515 points)

    I believe that Nestor enclosure has a JMicron RAID chipset, in testing that chipset as implemented into a RAID chassis by another manufacturer we were getting near 200 MB/sec  (sequential large file transfer tests) in a RAID5 over eSATA using a SATA card with a Silicon Image 3124 chipset. Drive model, as long as they are decent, like Seagate Barracuda or those WD Blacks, should not be a factor as the combined speed of that many drives is a lot faster than the RAID chipset is capable of. Ran same large file tests with same performance maximums - (200 MB/sec) running a simple RAID0 and a couple SSDs as well - to find the maximum throughput of the RAID chipset. Was faster over USB3 than eSATA.


    The E2P SATA card uses a Silicon Image 3132 chipset. That chipset will top out at 150 MB/sec, or around that. So yeah, it will slow that RAID a little bit, 25%-30% anyway.


    In a RAID10 you are effectively getting the striped speed of 2 drives. With those WD blacks, when the drives are empty, mechanical speed capability of 2 blacks would be up over 250 MB/sec. So the place where the speed limitation is when the drives are empty is first the 150 MB/sec E2P, then the 200 MB/sec JMicron RAID board.


    With RAID10 you will show a significant slow down of the RAID as you fill up the space with data. The RAID10, because it uses fewer drives in a pair of stripes, than a RAID5 which uses basically all but one of the drives in a larger stripe, the RAID10 will show the effects of filling up the space much sooner than the RAID5. If your RAID is anywhere near full it will slow a lot!


    I found the JMicon RAID quite functional. I would probably choose a RAID5 over a RAID10, but that is me. A faster SATA card will help a little, but part of the problem is the limitation of a RAID enclosure that is not really designed for speed. You are not going to make it a lot faster with a different card or a different RAID type.


    Make sure you always maintain a backup of your data - RAID10 does not mean backed up. All it takes is a failure of the RAID software or hardware to lose everything. A separate copy is essential.



  • 6. Re: Very slow external sata HD (lion)
    The hatter Level 9 Level 9 (58,885 points)

    I always gave the E2P more like 130MB/s in theory with less in practice. But that was on PCIe 1.1 and older drives at the time also.


    Sounds like a good setup all around, but would not deliver what 4-port card and enclosure with - but maybe not worth the cost to do so depending on the needs. Or a 4x/8x card which I assume means getting into SAS too.


    One new WD Black empty was 135MB/sec (internal, SATA II) or the speed of one drive is all you really get in that setup.

  • 7. Re: Very slow external sata HD (lion)
    Luca (LDF) Level 1 Level 1 (0 points)

    Tahnk you Rick and The Hatter for the explainations.

    Really clear and useful.


    I think I will have a try using internal HD for the workflow untill I can invest in a more faster card.

    I'll use the Nestor as good place where to backup.


    Thanks again!

  • 8. Re: Very slow external sata HD (lion)
    RatVega™ Level 4 Level 4 (1,910 points)

    You may want to look at SATA 3 boards like the Highpoint RR2721 which can provide SATA 3 RAID performance (both internal and external) at sane prices.


    I have a RR2720 in my Mac Pro 3,1 and get single spindle (JBOD) speeds of 145MB/sec using the Black Magic Design speed test. I'm setting up for a 6-spindle RAID 5 and a pair of eSATA ports. The RR2720 requires a few tricks, but the RR2721 and RR2722 should be plug-and-play.

  • 9. Re: Very slow external sata HD (lion)
    The hatter Level 9 Level 9 (58,885 points)

    but it is HPT; and there are other makes and cards. There is even bootable PCIe populated with SSD chips - bootable.


    Once I saw RAID6 and the limitations of RAID5, and given the size of today's drives people often use.


    HPT also has 4-port SATA3/6G $249 on Apple Store and elsewhere. Said to be bootable.

  • 10. Re: Very slow external sata HD (lion)
    RatVega™ Level 4 Level 4 (1,910 points)

    Yes it is HPT, and I've have good experiences with them. (However, their tech support isn't for newbies...)


    As far as I have been able to determine, a bootable 8-port SATA 3 board is close to $1000 and not internal. The (non-bootable) HPT I am using was about $170. The new HPT 2700 series have been getting good performance reviews. It's not the only solution out there but it is the cleanest and least expensive I've found.

  • 12. Re: Very slow external sata HD (lion)
    RatVega™ Level 4 Level 4 (1,910 points)

    The hatter wrote:


    Macintosh Performance Guide: OWC’s new Mercury Accelsior PCIe SSD for Blistering-fast Drive Performance


    Macintosh Performance Guide: OWC Accelsior PCIe SSD Reader Comment


    One word: bootable


    Also, Areca and ATTO.



    In my application, two words: Tiny and expensive.


    PCIe Slot 2 carries the RR2720 (which does not need to be bootable) to support the internal RAID. The Mac Pro 3,1 only has two PCIe 2.0 slots, so the Accelsior would be pointless. I'm planning on using an SSD on the on-board SATA II controller as a boot drive.


    BTW, do you know of a PCIe 2.0 expansion chassis that is sanely priced?

  • 13. Re: Very slow external sata HD (lion)
    joevt Level 1 Level 1 (0 points)

    How much bandwidth are you getting from the RR2720? It's a PCIe 2.0 x8 card (4000 MB/s). The PCIe 1.0 x4 slots in the Mac Pro 3,1 can do 1000 MB/s (maybe giving the RR2720 up to 800 MB/s ?).

  • 14. Re: Very slow external sata HD (lion)
    RatVega™ Level 4 Level 4 (1,910 points)

    Total bandwidth is a function of slot speed, spindle count, and drive transfer rate.  My RAID is not yet implemented because I only had Hitachi 3TB drives before the Thailand flooding (and ensuing shortages) drove prices completely out of sight. It will complete when prices normalize or I save enough money to buy 5 (maybe 6) Seagate 3TB drives (either way, cost is a significant issue.) I believe a RAID should use identical drives.


    The Mac Pro 3,1 has two 16x PCIe slots and two 4x. My RR2720 is in slot 2 (16x) so it should perform as advertised. If you actually require speeds of 800MB/sec and beyond, don't take the free advice of anyone on this (or any other) forum; work with a professional and contract for a specific level of performance.


    In the end you'll probably decide that reliability is your first criterion and all the speed you can get reliably is good enough. RAID 0 is like a racecar - sexy and exciting until it crashes. I'm looking for a RAID 5 that's fast enough (500-600MB/sec) to boost my overall throughput in disc-intensive work.

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