With USB3 JBOD enclosure, bottleneck with HDD?

Discussion in 'Mac Accessories' started by Luba, Jan 20, 2014.

  1. Luba macrumors 6502a

    Luba

    Joined:
    Apr 22, 2009
    #1
    I am looking to just move my 4 HDD in my 4,1 Mac Pro to an external USB3 JBOD enclosure (no RAID) to use with a nMP. If I do that will the bottleneck be with the HDDs? I know the theoretical USB3 speeds are greater than what HDD can push out, but real world speeds are lower than theoretical.

    I am thinking of getting this for $220: http://oyendigital.com/hard-drives/store/3R5-EB3-M.html

    Instead of the Pegasus2 R4 Diskless for $699: http://store.apple.com/us/product/H...kless-4bay-thunderbolt-2-raid-system?fnode=5f

    If I don't RAID and just want to use my 4 HDDs as I did in my oMP, any reason to get the Pegasus2 R4 Diskless with 4 bays over the Oyen Digital Mobius with 5 bays?
     
  2. ZnU macrumors regular

    Joined:
    May 24, 2006
    #2
    USB 3.0 is easily faster than a single 7200 RPM HDD. If you do something that generates substantial traffic in the same direction from multiple drives at the same time the interface could become a bottleneck — exactly at what point seems to vary pretty widely from one product to the next, presumably depending on what USB to SATA bridge each product uses. But if you're not using RAID, that probably won't be a very common access pattern.
     
  3. ActionableMango macrumors 604

    ActionableMango

    Joined:
    Sep 21, 2010
    #3
    Yes, HDD is slower than USB3 in both specs and real world speeds.
     
  4. Einz macrumors regular

    Einz

    Joined:
    Feb 14, 2008
    Location:
    Miami
    #4
    I have been using the Mobius 5-Bay for over 3 weeks now with my nMP. There is a sleep issue with USB 3. My Time Machine keeps disconnecting after sleep and had to reboot to get it working again. I communicated with their tech support was told a firmware update is coming soon to fix the issue. There is no guarantee the firmware will fix my problem. So, I decide to return it and get a TB enclosure.

    The Oyen support was very helpful and I decided to get their TB enclosure. But it is out of stock until the 30th. I went with the Pegasus2 R4 Diskless, with EPP I can get it for $620. Apple store said 2-3 delivery. I ordered it on Monday and just got shipped notice tonight.

    There is something odd about the Mobius. I have a Samsung 830 SDD and 3 hard drives in it. The mechanical Hd can read 170MB, while the SSD can't get pass 120MB. I like the Mobius, too bad it didn't work out for me.
     
  5. Luba thread starter macrumors 6502a

    Luba

    Joined:
    Apr 22, 2009
    #5
    What if I am accessing files at the same time from 2 or more HDDs, then would USB 3.0 be the bottleneck? In that rather unique situation, the Pegasus2 R4 would be better because TB2 wouldn't be the bottleneck even if 4 HDDs were sending data, correct?

    Btw, when USB 3.1 is approved and ready to go, could the nMP be updated to 3.1 by a simple firmware update or would it need a new 3.1 controller?

    ----------

    What's EPP? Education pricing?? I am eligible for Education pricing but when I went to the Apple Education store it was priced at $699, which is the regular price.
     
  6. ActionableMango macrumors 604

    ActionableMango

    Joined:
    Sep 21, 2010
    #6
    It depends on whether or not there is a dedicated USB controller for each port in the nMP, which I don't know. For example in the oMP I have a card with one controller for two ports and yes, it slows down quite a bit if you use both ports simultaneously. But there are also cards with a dedicated controller for each port and it wouldn't slow down at all.

    I don't know how the nMP is set up. You could start a new thread asking a nMP owner to test this.

    I don't see how. USB 3.1 has different connectors and provides power for 100 watts. An adapter might be able to overcome the connector problem, but I don't see how the nMP is going to come up with the power needed. Probably if you want USB 3.1 power in the future you'll need a PCIe card in a Thunderbolt enclosure with a separate power cable.
     
  7. Einz macrumors regular

    Einz

    Joined:
    Feb 14, 2008
    Location:
    Miami
    #7

    EPP=employee purchase program.
     
  8. Einz macrumors regular

    Einz

    Joined:
    Feb 14, 2008
    Location:
    Miami
    #8
    I got my Pegasus2 R4 Diskless. It must have been s dud. It keeps hanging my Mac. It was fast when it was working. I ended up returning it.

    I finally got the new firmware for my Mobius. It fixed my problem. For my needs, TB2 was over kill and save me $400 for some thing else.
     
  9. VirtualRain macrumors 603

    VirtualRain

    Joined:
    Aug 1, 2008
    Location:
    Vancouver, BC
    #9
    Good to hear, but what about the read speeds of your SSDs in the Mobius? Can you give us a more thorough review with the new firmware? Also, what's the noise like? Build quality? etc. :)
     
  10. shaunp macrumors 65816

    Joined:
    Nov 5, 2010
    #10
    You would only ever get the maximum transfer rate of a single HDD, but if this is enough then go for it. I've got a Pegasus 2 R4 and I easily get over 500MB/s sustained. You also get not redundancy on the drives with the solution you are proposing.

    If you don't need the redundancy or the speed of a single HDD is enough then go for it. Everyone has their own requirements you know yours better than anyone.
     
  11. Einz macrumors regular

    Einz

    Joined:
    Feb 14, 2008
    Location:
    Miami
    #11

    The SSD read/write is bad in the Mobius. It uses the SATA 2 connector. It can't get pass 120MB. What puzzles me is that my mechanical Seagate can R/W 150Mb in it.

    The problem with the old firmware was that the unit would power down when there is no access for a period of time even thou the Mac is still on (not sleeping). The Finder gets confused and can't access the drives. I had to reboot to reconnect. With the new firmware, I didn't have any problem for the past few days.

    The build is pretty good and it's quieter than the Pegasus2 R4. I used it mainly for my media and backups. For faster access like photos. I put my SSD in faster USB enclosure.http://www.amazon.com/Optimized-Ina...e=UTF8&qid=1391070578&sr=1-3&keywords=inateck
    The write is 334MB and read is 364MB.

    When the Pegasus was working the read/write was about 480MB with the SSD. The speed is nice. But I just can't justify another $400 for something I don't need. I love Apple's return policy.
     
  12. VirtualRain macrumors 603

    VirtualRain

    Joined:
    Aug 1, 2008
    Location:
    Vancouver, BC
    #12
    Interesting. Thanks. So the Mobius is good for spinning disks only then. :rolleyes:
     
  13. Einz macrumors regular

    Einz

    Joined:
    Feb 14, 2008
    Location:
    Miami
    #13
    Yes. It's SATA 2, so it will not take advantage of the SSD's speed. I can get it to R/W 200MB when using eSATA connection with my old Mac.
     
  14. Luba thread starter macrumors 6502a

    Luba

    Joined:
    Apr 22, 2009
    #14
    What's the R/W of the 4,1 Mac Pro with 4 HDDs not in RAID and using SATA2? Would using the Möbius on a nMP via USB3 be better or worse? Same?
     

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