Getting slow speeds RAID

Discussion in 'Mac Pro' started by comatory, Oct 31, 2012.

  1. comatory macrumors 6502a

    comatory

    Joined:
    Apr 10, 2012
    #1
    I have installed 5 drives in 2009 Mac Pro - SSD is in Optibay and there are four HDD in bays.

    Bay 1 - stock 640GB Hitachi drive
    Bay 2+3 - 750GB WD 750GB Caviar SE16 drives in striped RAID via Disk Utility
    Bay 4 WD Caviar Green

    The RAID is slowest of them all which sucks as I wanted to use it as a scratchdisk for HD video editing. Not sure if Im doing something wrong as this is my first time setting up RAID.
    I might have been a fool though, I bought those two 750GB drives second hand without checking the specs - seller told me they're 7200RPM SATA II drives. I figured it should be enough to saturate Mac Pro's bus. Can anyone elaborate on that?

    I downloaded AJA System Test
    Hitachi drive gets 100MBs write/107 read
    WD Caviar gets 118/130
    RAID drives get only 85/88

    Tested on 1GB file. I also tried transferring 3GB file to various disks and the RAID is indeed the slowest of them all. Anyone has any idea? My hunch is that I just chose old drives.
     
  2. Loa macrumors 65816

    Loa

    Joined:
    May 5, 2003
    Location:
    Québec
    #2
    Hello,

    These are very old drives. If they've been used hard, they're on their last legs... You could hope for 60MB/s write, and 80MB/s read when they worked optimally back in 2007.

    Your RAID's speed is indeed slow, but maybe one (or two) of the drive is defective, dying.

    Did you use Disk Utility to set-up your RAID?

    Loa

    P.S. Just to be sure, you did create a RAID0 (or splice), and not a RAID1 (or mirror), yes?
     
  3. comatory thread starter macrumors 6502a

    comatory

    Joined:
    Apr 10, 2012
    #3
    Man that sucks, Im so stupid I should have checked specs... I somehow assumed that SATA II drives in RAID0 will be really fast. Well, christmas is soon.

    What drives should I get, any good recommendations? Id like to have decent speed, maybe around 200MB/s (can I expect that from spinning drives?) in RAID0. 500GB in size would be sufficient and if the drives arent super loud.

    Yes I used Disk Utility. Im pretty sure I selected "striped set" in Disk Utility, using OS X 10.8.2.
     
  4. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #4
    I run a pair of 1TB WD 7200rpm SATA-II disks (data libraries) as RAID-0 in my 2008 Mac Pro and they test at 140 MB/s using BlackMagic Speed Test.

    I also have a pair of OWC SATA-II SSD drives (boot/apps) also as RAID-0 in the same machine and they test at 380 MB/s using the same test.

    Both are using the standard software raid from Disk Utility



    -howard
     
  5. comatory thread starter macrumors 6502a

    comatory

    Joined:
    Apr 10, 2012
    #5
    which model is it exactly?

    also I have no idea how fast RAID0 with platters are? I thought I could be getting around 180-200 with 7200RPM drives.
     
  6. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #6
    Which model of what?

    It is a 2008 3,1 model Mac Pro with dual 2.8 GHz Quad Core

    The hard disks are standard WDC WD1001FALS drives (2 x 1TB in RAID-0).

    The SSD drives are OWC Mercury Electra 3G SSD (2 x 240 GB in RAID-0)

    You can download the BlackMagic Disk Test for free at the App store.




    -howard
     
  7. comatory thread starter macrumors 6502a

    comatory

    Joined:
    Apr 10, 2012
    #7
    Thanks I thought the model of classic HDDs, looking to replace those slow ones in month or two. I mean they do what I need them to do but having more speed would be better, especially in multilayer AE projects (20+).

    That drive doesnt look bad but I could have 40% off on Seagate Barracuda's 500GB model ST500DM002. They look on par with that WD. What do you think of those?

    I'm running 2009 Quad.
     
  8. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #8
    Those WD drives have been running for several years in my RAID-0 as my total system drive until I split the OS and apps off to a separate SSD (now a pair in RAID-0). I had always been a Seagate fan, but had some troubles with a series of Seagate models and bought theWD drives at that time. I would probably get current Seagate models again if I found a good price on them.


    -howard
     
  9. avemestr macrumors regular

    Joined:
    Aug 14, 2012
    #9
    I have a 600GB Intel Series 520 SSD. It was included, when I bought a 2009 MP some time ago. I thought "great, it's an SSD!". Test results:

    DiskSpeedTest SSD 1GB: 219MB/s write. 263MB/s read.
    DiskSpeedTest SSD 5GB: 217MB/s write. 267MB/s read.

    But then today I received two 2TB WD Black drives. Setup in RAID-0 (Striped) with disk utility. Test results:

    DiskSpeedTest HDD 1GB: 253MB/s write. 255MB/s read.
    DiskSpeedTest HDD 5GB: 255MB/s write. 253MB/s read.

    So, the HDDs in RAID perform on par with the SSD. With three caveats:

    1) Blackmagicdesign Disk Speed Test tests with quite large file sizes. SSD should perform better than HDDs in small file random access.

    2) My SSD holds all data at the moment. The HDDs are entirely empty and just out of the packaging.

    3) Current-gen SSDs will probably wipe the floor of my SSD/HDDs.

    I did not intend to hijack the thread, but I feel it pretty safe to say HDDs can perform much better than what OP experiences.
     
  10. wonderspark macrumors 68030

    wonderspark

    Joined:
    Feb 4, 2010
    Location:
    Oregon
    #10
    I have a pair of stock Apple (Hitachi) 1TB HDDs slots 2&3 in OS X software RAID 0 on my 2009 Mac Pro, and they get 220MB/sec read and write. It depends on the individual throughput of the HDDs, and if they're all healthy.
     
  11. Loa macrumors 65816

    Loa

    Joined:
    May 5, 2003
    Location:
    Québec
    #11
    Hello,

    I have a pair of 2TB Caviar Blacks in RAID0. Blackmagic Disk Speed Test tells me they're running at 245MB/s Read and about the same for Write.

    Loa
     
  12. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #12
    So ... it looks like "modern" drives outperform my older drives in RAID-0 with almost double the data rate. :cool:

    What do you think is responsible for the performance increase?:

    2TB native capacity vs. 1TB drives
    64MB cache vs. 32MB
    SATA-III drives vs. SATA-II running on SATA-II interface
     
  13. Loa macrumors 65816

    Loa

    Joined:
    May 5, 2003
    Location:
    Québec
    #13
    Comparing 7200rpm drives, young and old, there's only one answer: data density.

    Loa
     
  14. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #14
    Yeah ... that was what I was thinking too. That would also help explain the OP's abysmal performance with old 750 GB drives.

    I guess if I want more performance, I should probably move up to 2 TB drives when I replace my existing 1 TB drives (which I have been thinking of doing since they have been running 24/7 for about 3 years now).


    -howard
     
  15. Loa macrumors 65816

    Loa

    Joined:
    May 5, 2003
    Location:
    Québec
    #15
    Predicting Hard Drive failure is a tricky thing: statistics only apply to very large groups of HDs... Yours could lasts for years and years still.

    Having a good back-up strategy, on the other hand, is always a good bet! :)

    Loa
     
  16. 666sheep macrumors 68040

    666sheep

    Joined:
    Dec 7, 2009
    Location:
    Poland
    #16
    Yep, this is the case. And these are 4-platter drives what always has an impact on performance. I use 3x 500GB Samsung 1-platter HDDs in RAID0 and after few years I still get 327/327MB with AJA even if I have half of RAID space used.
     
  17. Loa macrumors 65816

    Loa

    Joined:
    May 5, 2003
    Location:
    Québec
    #17
    Indirectly only, as an indicator of density. The more platters you have, the less density for a given drive size.

    Loa
     
  18. comatory thread starter macrumors 6502a

    comatory

    Joined:
    Apr 10, 2012
    #18
    Thanks for helpful insights. Now I only need to decide which one to buy.

    Since I'm getting 40 percent off on those Seagate drives, I'd like to go with them but if WD Black Caviars are major improvement, I'm willing to invest more.

    Are there any benchmarks online for those two drives in RAID configurations? They are both good brands and look high quality. Can't decide really.
     
  19. avemestr macrumors regular

    Joined:
    Aug 14, 2012
    #19
    A lot of people have great experiences with Seagate.
    A lot of people have great experiences with WD.
    A lot of people have bad experiences with Seagate.
    A lot of people have bad experiences with WD.

    It's quite meaningless to ask on a forum which is the best. You'll get 20 replies in both directions, but none will take into the account the performance of the millions of WD and Seagate drives sold every year. Harddrives are in general stable, but there's always the small percentage of bad drives.

    But I prefer WD Blacks.

    The WD Blacks will probably be faster in benchmarks. If you'll feel it in your daily work is quite impossible to say. Probably not.

    In conclusion: Buy whatever drive you like. It'll probably do the job just fine. Harddrives today are fast and reliable.
     
  20. Loa macrumors 65816

    Loa

    Joined:
    May 5, 2003
    Location:
    Québec
    #20
    +1.

    Both are good companies.

    Loa
     

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