Mac Pro (5,1), MaxConnect, Areca, HGST He8 SAS Pin 3 Issue

Discussion in 'Mac Pro' started by zebity, May 17, 2015.

  1. zebity, May 17, 2015
    Last edited: May 17, 2015

    zebity macrumors member

    Aug 1, 2008
    Hi Mac'ers,

    I have just been testing with Areca 1882i Internal RAID card and MaxConnect BackPlane (from MaxUpgrades: with latest HGST Ultrastar He8 12Gb/sec SAS disk.

    For those who are not aware the MaxConnect backplane is a rather ingenious way to get around the performance and disk size limit of Mac Pro.

    The MaxConnect has special trays into which you install your shiny new faster and bigger disks, in place of standard Mac Pro sled. They then take the power from the inbuilt SATA/SAS slots and use a set of mini SAS to 4 SATA/SAS serial cables to provide the data path. These are then terminated on internal SAS/SATA connector of PCIe RAID card (in my case this is an Areca ARC-1882i).

    In my setup I had 4 x 4TB 6Gb/sec SATA drives with 3 set up as RAID 5 and the 4th having a replicated backup. However with 3 x 4TB S disk resulting in total 8TB storage I have gotten past 4TB limit of my 4th 4TB SATA backup disk and so decided to upgrade this to 6TB HGST He8 12Gb/sec SAS drive.

    I went for SAS rather than SATA as this provides 12Gb/sec while SATA is only 6Gb/sec and I also decided to upgrade the ARC-1882 to an ARC-1883 series card which has 12Gb/sec support.

    I expected do the upgrade by:
    1. Remove 4TB back up disk and replace by 6TB disk
    2. Carbon Copy Clone RAID 5 contents (3 x 4TB Disks) to the single 6TB disk
    3. Remove ARC-1882i and replace with ARC-1883lp
    4. Reconnect all drives to ARC-1883lp
    4. Reboot computer from single 6TB disk
    5. Regenerate (if required...) RAID 5 on ARC-1883lp
    6. Carbon Copy Clone 6TB contents over to RAID 5 (3 x 4TB Disks)

    This a quite a few steps and leaves you vulnerable to single disk failure, so I also did Time Machine backup to main Xserve back up server.

    Here is how far I got...

    Step 1. Replace 4TB back up disk with 6TB He8 SAS disk.

    Disk is not visible via management interface...

    Step 1.1.
    Contact Areca support as determine if there was a know compatibility problem with He8 (which are 4096 sector drives) and 1882.
    They advised to upgrade the 1882 to latest firmware, which I did via the provided cli64 interface.

    Step 1.2.
    NOTE: I could not get the firmware upgrade to work using the HTML UI interface, but cli64 interface worked a charm. The upgrade requires that you load 3 separate files.

    Rebooted after upgrade and still cannot see He8 SAS drive within Areca management interface

    Step 1.3.
    Recontact Areca support, they cryptically advise that there might be a problem with some "legacy" SATA backplanes and 12Gb/sec SAS backplanes, which results in failure to power up drive...

    Step 1.4.
    Download the HGST 4TB SATA disk specifications and the 6TB He8 SAS disk specifications and look at all the Pin Out details.

    Ahhh it appears that 12Gb/sec SAS has taken over "Pin 3" power for a "Power Disable" function which provides the equivalent of a hard reset capability, while on SATA this was used to provide a vendor specific function for circuit "Pre-Charging".

    So answer appears to be that I need to do some physical surgery to stop power "Pin 3" from getting any voltage.

    With the "MaxConnect" backplane I could achieve this by cutting one of the internal transfer wires, but reading the HGST He8 manual it also says that power pins P1, P2 & P3 are all internally tired. So this would mean cutting all three transfer wires.

    Given that it was only speculative that Pin 3 was the cause of the problem, I was not too keen to start chopping up the MaxConnect backplane, so needed an alternate.

    Step 1.5.
    Simple solution put masking tape across power pins P1, P2 & P3 on MaxConnect connector. This would then isolate these and provide equivalent of cutting but be reversible in the event that Pin 3 was not the problem.

    Step 1.6.
    With masking tape positioned across P1, P2 & P3 reboot machine.

    Ok!! He8 SAS now visible within Areca management interface, so configure it as pass-through disk and it appears as an un-initialised disk on Mac Pro.

    Summary: 12Gb/sec SAS Pin 3 could results in compatibility problems with Mac Pro internal disk SATA power. For HGST He8 SAS ensure that you have no power coming on P1, P2 & P3.

    I am now waiting for 1883 to arrive before I complete steps 3 - 6 .

    I will provide a performance update on impact of ARC-1883 vs ARC-1882 once complete.


    (Mac Pro with 2 x 3.46GHz, Small Tree 10Gbe, Areca 1882/3 & Nvidia Titan)
  2. crjackson2134 macrumors 68040


    Mar 6, 2013
    Charlotte, NC
    I'm not aware of any disk size limits other than the 8 exabyte limit of the HFS+ file system. Please elaborate.
  3. zebity thread starter macrumors member

    Aug 1, 2008
    Problem was with Mac Pro RAID card

    Hi crjackson,

    My problem was with Mac Pro RAID card I had installed originally.

    I always use RAID to get better performance and protect against disk failure, which is inevitable....

    The old RAID card had a 2.2TB limit and max 3Gb/sec disk interface. So in 3 disk RAID 5 config, you got 4.4TB max. It was also not fast enough for 4K video.

    That was why I moved to Areca/MaxConnect. This now let's me have very large internal storage with enough throughput for 4k video (ProRes only).


  4. ShawnF macrumors regular

    May 10, 2014
    Man that HGST Ultrastar He8 costs about $1400 on Amazon!
  5. zebity, May 17, 2015
    Last edited: May 17, 2015

    zebity thread starter macrumors member

    Aug 1, 2008
    He8 comes in 6tb & 8tb


    He8 series comes in 8TB and 6TB sizes.

    You can get 6TB 12Gb/sec SAS model on eBay new for around $600.

    Better value than 8TB model.

    But still enough to cause significant worry when Pin P3 change resulted in it looking like a dead disk or major technical hitch.

    I went for He8 series to test 12Gb/sec performance and also see impact of moving from 512e to 4Kn sector sizes.

    12Gb/sec SAS in also good for future SSD.

  6. wa5655 macrumors member

    Jun 12, 2010
    Hi, zebity

    I am going to be a little off topic here. How is the fan noise of 1883i? I have owned previous gen Areca card before, the fan noise can be quite loud.

    Performance wise, aren't we still limited by PCIE2--since this is a PCIE3 card. How does it improved vs say 1882 in a cMP (same PCIE2 slot)?

    Thanks for your insight.
  7. zebity, May 22, 2015
    Last edited: May 25, 2015

    zebity thread starter macrumors member

    Aug 1, 2008
    Still waiting for new sff

    Hi waxxxx,

    I am still waiting for arrival of new SFF-8643 internal connection cables, before I can get 1883 running. Unfortunately they are taking ages to arrive.
    I will let you know fan noise level once up and running.
    This was never an issue with 1882 series.


  8. zebity, May 25, 2015
    Last edited: May 25, 2015

    zebity thread starter macrumors member

    Aug 1, 2008
    Areca ARC-1883lp noise level


    Got new cables and installed ARC-1883lp.

    This was much simpler than expected.

    1. Do backups
    2. Remove 1882 and cabling
    3. Install 1883 and new cabling
    4. Boot computer from usb OS X with Areca drivers installed and firmware download
    5. After booting prior RAID set disk is visible, so Areca must be getting RAID configure from disks
    6. Run browser to configure pass-through-disk (the He8) and EFI bios selection
    7. Open Terminal and run cli64 to upgrade firmware to same version used on prior 1882
    8. Reboot and remove usb
    9. Reboots from existing RAID 5 set without need to regenerate disk

    Fact 1883 rebooted from prior RAID 5 set was huge time saver, as doing a disk initialisation takes around 24 hours ....

    Fan noise from 1883 is no problem. ... It might be more on an issue for those using larger higher density models ....

    Performance wise 1883 has greater than 400MB/sec write (no doubt help by larger cache than 1882).

    Playing 4K Cineform video (to test read speed) gets same read performance from RAID 5 set (3 x 6Gb/sec SATA) as single 12Gb/sec SAS disk (He8), at around 12 fps, while 4K ProRes plays from both RAID 5 & single 12Gb/sec SATA (He8) at full frame rate.


  9. zebity, Jun 27, 2015
    Last edited: Jun 27, 2015

    zebity thread starter macrumors member

    Aug 1, 2008
    Areca 1883 Users,

    By default 1883 will be in PCIe Gen 3 mode.

    This results in in running at 2.5GT/sec in Mac Pro 5,1 .

    There is a configure setting for "PCIE Gen3" which should be set to "Disable".

    Then with two reboots you will see card is running at 5GT/sec .

    Testing performance showed little difference though...

    Expect that this is because disks are bottleneck still.

  10. Daniel Reed, Apr 19, 2017
    Last edited: Apr 19, 2017

    Daniel Reed macrumors 6502

    Daniel Reed

    Sep 9, 2016
    San Francisco
    12GBps from spinning disks requires a minimum of 60 He8 disks striped in a RAID-0

    Playing back 6K RED RAW w/ 4:1 compression in real-time/24fps requires less then 300MBps

    A single He8 disk will play back 4K (RED or ProRes) at 24fps over USB3

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