RAID 0 performance?

Discussion in 'Mac Pro' started by bobbydaz, Sep 20, 2010.

  1. bobbydaz macrumors regular

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    #1
    Just interested to know what performance boost I can expect by switching to a 2x 1TB RAID 0 set-up for my work files, System and Apps will be on a separate SSD.

    Using mainly Photoshop (files 100mb up to max of 1gb) how much will my open and save times improve?
     
  2. Hellhammer Moderator

    Hellhammer

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    #2
    RAID 0 theoretically doubles the read and write speeds. In real world, it depends on the task but it should speed the things up
     
  3. maflynn Moderator

    maflynn

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    #3
    When I was running a RAID-0 setup, I noticed a significant decrease in boot times and program start up times, like photoshop.

    If you're going with a RAID-0 setup, on your main drives, I'd be sure to have a solid backup regiment because if unit fails you lose all of your data.
     
  4. bobbydaz thread starter macrumors regular

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    #4
    that's what I thought but haven't managed to find any test results to see what can actually be achieved.
     
  5. Hellhammer Moderator

    Hellhammer

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    #5
    Some benchmarks

    http://www.anandtech.com/show/2212/8
    http://www.anandtech.com/show/1371/5

    I know they are using different drives but that's more to just compare RAID 0 and single HD. If you can't afford a big SSD, then RAIDing is you best solution. Just remember to have a solid backup as mentioned above
     
  6. bobbydaz thread starter macrumors regular

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    #6
    thanks for the links. I would like a large SSD but I though it wasn't a good idea to use SSD for constant writes, I would be writing data to it constantly 8 hours a day, 5 days a week!
     
  7. Loa macrumors 65816

    Loa

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    #7
    Hello OP,

    I just checked for Photoshop Open and Save times, using a single HD or a 4 disk RAID0. Test was made on a 2009 MP, with CS5, with 8GB of RAM. Test file is a 12MPx file with lots of complex layers/masks, and weighs 414MB.

    The single HD is on an external eSATA dock, but you'll see that it makes no difference...

    Open time:
    -For single HD, External eSATA: 10 seconds
    -For 4 disk RAID0: Internal: 10 seconds

    Save time:
    -For single HD, External eSATA: 40 seconds
    -For 4 disk RAID0: Internal: 39 seconds

    Bottle neck is clearly not the transfer speed! If you want faster Open/Save times, you need a faster CPU.

    Loa
     
  8. Honumaui macrumors 6502a

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    Apr 18, 2008
    #8
    look into Raid 10 or 1+0 both the same ?

    safe and speed with no controller to buy ?

    400 meg file on my setup is about 3.7 seconds to open and save
     
  9. Loa macrumors 65816

    Loa

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    #9
    Nothing in your described set-up should be faster than a 4 disk RAID0 of enterprise grade drives.

    What's the rest of your system? Saving a 400MB file in PS is always long, I'm curious how you managed 4 seconds

    Loa
     
  10. Honumaui macrumors 6502a

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    #10
    sorry about that :) here is my setup

    actual file size was 396.5 megs


    use a 100 gig SSD for boot
    Areca 1222x for storage and I have older 750 gig HDDs in it ! not even faster new ones :) going to though next spring put some new ones in wait for the price of the RE4 to drop more
    but its setup as Raid 6 also have the battery module on it
    2 40 gig SSD in raid 0 for scratch
    backup time machine is a standalone 5 disc raid 5 with 2 TB drives
    the other is a JBOD PM case
    then offsite storage as well
     
  11. bobbydaz thread starter macrumors regular

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    #11
    Thanks for the figures. A bit worrying that it sounds like it makes no difference at all. Am I wasting my time and money on a RAID 0 set up?
     
  12. Loa macrumors 65816

    Loa

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    #12
    Honumaui: I can't understand how Photoshop can open or save a 400MB file in 4 seconds, even with your set-up. Is it a PSD file with lots of complex layers/masks?

    I can save such a file to JPEG in a few seconds, but not as a complex PSD file. It's always long as there are many operations that PS does to it before even writing it to the disk.

    Bobbydaz: I'm not sure about the real world applications of RAID0 unless you have to move a lot of really large files many times per day. There are probably a few apps that see significant gains (video work, most likely), but aside from that I've been underwhelmed by actual performance gain. Benchmarked throughput is impressive, but actual time saved in your typical workflow is entirely application dependent. Doesn't seem to help me with PS CS5.

    Loa
     
  13. Honumaui macrumors 6502a

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  14. bobbydaz thread starter macrumors regular

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    #14
    Just to throw something else into the mix - Would a single Velociraptor be a better option than RAID 0?
     
  15. Honumaui macrumors 6502a

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    #15
    I might say yes if its one of the latest 600GB ones ? but without testing ? who knows unless someone else out their has ? and that depends on the raid 0 ?
    if its two WD black 2TB shortstroked I might give the lead back to the 2TB raid 0 short stroked WD blacks then ?

    the other thing in real world a short stroked WD 2TB would not be bad as the rest of the HDD can be used for BU ?

    but if you have a raptor around ? you could try it ?
     
  16. Honumaui macrumors 6502a

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    #16
    after you open that file for grins go down to the lower left of the document and see what the scratch size is ?
    and what was the efficiency ?
     
  17. Loa macrumors 65816

    Loa

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    #17
    Size: 1.12G/5.19G
    Efficiency: 98%

    Loa
     
  18. Honumaui macrumors 6502a

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    #18
    thats not bad then for opening
    you can also set your info window to show your efficiency and such might be interesting to keep a eye on it when you are working find where things get slower or use scratch etc.. ?
    remember its just for the last thing done ? so complex actions wont record the total action just the last thing done :) but it can show a lot as you are doing stuff :)
     
  19. Loa macrumors 65816

    Loa

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    #19
    Hello,

    I know about scratch performance. What I still don't understand is how your system can save a 400MB PSD file in 4 seconds. I don't have the fastest set-up on the planet, but a 2009MP with a SSD boot drive and a 4 disk RAID0 set should be up there...

    Getting 40 seconds while you get 4 seconds is a huge difference.

    Loa
     
  20. nanofrog macrumors G4

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    #20
    The difference is a combination of the Areca's cache and he's running 8x disks in the array. ;) So even with older (slower) disks, his array ends up capable of a faster sustained throughput.

    For example, if you figure 85MB/s per disk in the level 6, it should generate ~510MB/s, while 4x 100MB/s HDD's in a stripe set only generate 400MB/s. Rather obvious.

    As per why it comes up 4x faster than your system, is yours is a software implementation (no cache or separate processor, though the actual RAID load should be very low). But it's still consuming system resources that could otherwise be used on the processing (assuming the test file is the same, which I'm thinking there may be more differences than seem evident from the information provided).

    To give you an example, if I disable the cache in the ARC-1231ML (8x member RAID5), it can generate ~760MB/s sustained. But with the cache enabled, it can jump to ~1.4GB/s (file fits within the 2GB cache). So cache can make a significant difference.
     
  21. Honumaui macrumors 6502a

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    #21
    Ditto Nanofrog on why

    I also have 24 gigs of memory ? raid 0 2 disc SSD for cache and SSD for boot and Areca raid with 8 discs like NanoFrog mentioned

    I dont check compatability ? that can add time on save ?

    think of it this way the Areca or other true good raid cards have their own processor and their own memory and are why some of us preach once you want to get serious you look into this ? the downside is price ?
    starting point $1000 without discs

    a 400 meg file is pretty small when it comes to throwing them at the raid controller :)

    and when I get the 1880 next season and see what discs are ripping then :) it will only get better :)
     
  22. Loa macrumors 65816

    Loa

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    #22
    Hello,

    I did think about that RAID card's cache. On the other hand, if throughput is the key to PS saving speeds, why does it take the exact same amount time to save the same file on an external eSATA single HD than it takes on my 4 disks RAID0 set?

    Loa
     
  23. nanofrog macrumors G4

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    #23
    From what I can tell, you're a tad short on RAM, so the system is consuming cycles for paging (remember, you've the OS, PS, and RAID functions sharing resources on your system simultaneously).

    The RAID card can take over the RAID functionality (i.e. more to do with getting the completed data off the RAM and into the cache on the card than the clock cycles used for the RAID calculations, which aren't much in terms of CPU utilization % for stripe sets). This frees up RAM to help workflow.

    In your case, there's not quite enough from what I can tell (going by the 98% efficiency for PS), so it's paging RAM to/from disk (adds latency to completing the write you're measuring). Honumaui's system is running at 100% IIRC from a previous post made.

    Can you borrow any RAM to get a larger capacity and retest?
    If so, you can see if that 2% increase makes a real world difference in your system.
     
  24. Honumaui macrumors 6502a

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    #24
    could be if you have checked compatibility mode ? this will slow things down :) about %20 or more ?

    it very well could be our file ? is yours in 16 bit mode ? that will do it ?
    or the ram ? as mentioned ?

    it is a bit of a jump ? for a 400 meg file ? I agree :)

    for grins go here
    http://forums.macrumors.com/showpost.php?p=10983737&postcount=76
    do that ? down the thread #103 was my time and this was on my older 3,1 mac with only 14 gigs ? have not done it on my new one yet ?

    would be cool to see your times and post em up :)


    cause it could very well be your file will be close on my setup ?

    I like figuring stuff like this out so game if you are to do some testing :)

    save is throttled by one CPU !!!! sadly but if you can dump a bunch on that cache and then have it deal with it quick its going to help I found ? but again this much ? I think we are missing something between us maybe ?

    for grins in testing that PS file my read is 2527.2 MB/s
    checking disable cache it was 2763.4 MB/s

    but the more I think ? their is something going on we are not catching :)
     
  25. Honumaui macrumors 6502a

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    #25
    OK for grins I took the instructions and made a few changes
    1. Open a new doc, 20inches x 20 inches i at 300ppi and color mode RGB 8 bit white background color profile sRGB

    2. Filter -> Noise-> Add Noise -> Gaussian, 100%

    3. Duplicate that layer 3 times to give you a total of four.

    4. Make the top layer multiply, the next one down screen mode, the next one down, overlay.

    5. Don't flatten. Save as a .PSD do not check compatibility mode when saving

    I end up with a file that is 413.8 MB on disc

    my open time was 4.1 seconds
    save time was 3.8 seconds

    I also have Lightroom and a ton of stuff open will do it from a fresh restart in a bit ?

    this might help us get to the bottom :) and I really hope your time is 4 seconds :) cause it should be faster than what it is ? again I think we have a missing link :) so this would be fun to see what others get also for open and save :)
     

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