Is it worth raiding 2x Hitachi 3TB 7200rpm Deskstars?

Discussion in 'Mac Pro' started by sparkie7, Aug 30, 2011.

  1. sparkie7 macrumors 68000

    sparkie7

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    Oct 17, 2008
    #1
    I have two on order. I can either slot them into my Mac Pro 3,1 and have then as storage drives for all my photography and video files. Or I was thinking of setting up a (software) RAID.

    Is it possible to say, partition them so each has 3x 1TB partitions. Then RAID one of the 1TB partitions from each drive? Say as a scratch disk. Probably better using smaller partitions, say 250GB. Any advice/suggestions?

    Leaving the other 4x 1TB partitions as storage.
     
  2. mulo macrumors 68020

    mulo

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    #2
    I believe you can only raid the entire drive, i.e. not just a partition.
     
  3. sparkie7 thread starter macrumors 68000

    sparkie7

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    #3
    awe man, so it isn't so.

    i thought it was possible with equal partitions

    anyone confirm either way?
     
  4. khollister macrumors 6502a

    khollister

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    #4
    You can RAID partitions. I have done this for a scratch disk for Photoshop myself with a pair of WD Caviar Black drives.
     
  5. Inconsequential macrumors 68000

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    #5
    Dunno why you'd want to tho unless you have large files.

    An SSD boot drive with the scratch on there would be quicker :confused:
     
  6. sparkie7 thread starter macrumors 68000

    sparkie7

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    #6
    I do have an SSD as boot & application drive. But using it also for scratch would wear it out to quickly

    ----------

    Great thanks. Diglloyd confirms this also.

    What size are your WD Caviars and what were your partition sizes. I assume you're using Disk Utility to software partition?
     
  7. blazeken996 macrumors member

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    #7
    First of all. I don't think the motherboard can recognize 3TB hard drives. So you might wanna watch for that. Maybe ask Apple and see if they're Mac Pros support 2TB+ drives.
     
  8. Inconsequential macrumors 68000

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    #8
    Erm, no it wouldn't'!?

    See: http://www.xtremesystems.org/forums/showthread.php?271063-SSD-Write-Endurance-25nm-Vs-34nm

    The Samsung wrote 478 TB to the drive before failure. Even at at 100Gb a day thats 13 years!!!!

    And besides, even when it wouldn't write anymore the data was still readable.

    SSDs aren't fragile.
     
  9. khollister macrumors 6502a

    khollister

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    #9
    Also incorrect. Mac Pro's work just fine with 3TB - I have one of those installed as well.
     
  10. khollister macrumors 6502a

    khollister

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    #10
    2TB (the older SATA II with 32MB caches). I have a 100 GB stripe (50+50) at the front of the drives for CS5/NX2 scratch, another 600GB stripe (300+300) for audio sample libraries) and the remainder of the drives as 2 individual volumes for archival stuff.
     
  11. sparkie7 thread starter macrumors 68000

    sparkie7

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    #11
    Thanks. Do you notice the stripe arrays as being much faster, as in double? as they are reading/writing to both drives at once.

    Any ideas what the transfer rates are with respect to the 3GB SATAII?
     
  12. khollister macrumors 6502a

    khollister

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    #12
    I get about 200 MBs write and 230 MBs read according to the AJA benchmark. Single WD Black is about 115 write and 130 read near the outside (front) of the disk (same place the stripe partitions are).
     
  13. sparkie7 thread starter macrumors 68000

    sparkie7

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    #13
    Whats AJA? - I assume its drive testing software?


    Are you able to specify which sectors/locations your partitions are??
     
  14. khollister macrumors 6502a

    khollister

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    #14
    http://www.aja.com/ajashare/AJASystemTest.zip - free test software from a manufacturer of video editing systems

    Disk Utility creates partitions from the outside of the disk in. The first partition you create uses the fastest part of the disk, and each subsequent partition uses the next available section on the platters working towards the inside (closest to the spindle).

    It is an angular velocity versus linear velocity "thing". for a given spindle speed, sectors at the outside of a platter have a higher linear velocity due to the greater distance from the point of rotation, and therefore sweep more data under the heads in a given amount of time. It's the same reason larger capacity drives are usually faster - greater areal density due to either more data per platter (more advanced media & head technology) or more platters & more heads (the brute force approach).

    The Hitachi 3TB drives use the brute force approach - 5 platters instead of the 3 (I believe) on the 2TB models.
     
  15. sparkie7 thread starter macrumors 68000

    sparkie7

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    #15
    thanks for the info. very helpful. was reading about this on Diglloyd too.

    whats your advice on partitioning 2x Hitachi 3TB drives? -- in terms of sizes/usage?

    I was thinking..

    H1: Partition 1 > RAID 0 Stripe 100GB (Photoshop scratch of 200GB total)
    H1: Partition 2 > RAID 0 Stripe 400GB (2nd Photoshop scratch or for video, 800GB total)
    H1: Partition 3 > 1TB (Work documents)
    H1: Partition 4 > 1TB (Photography storage)
    H1: Partition 5 > 500GB (spare 1)

    H2: Partition 1 > RAID 0 Stripe 100GB (Photoshop scratch of 200GB total)
    H2: Partition 2 > RAID 0 Stripe 400GB (2nd Photoshop scratch or for video, 800GB total)
    H2: Partition 3 > 1TB (CCC back up volume of: Work documents)
    H2: Partition 4 > 1TB (CCC back up volume of: Photography storage)
    H2: Partition 5 > 500GB (spare 2)

    Do you think the above works?

    PS what software is NX2 in post #10
     
  16. nanofrog macrumors G4

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    #16
    I wouldn't recommend doing this, as it appears that you'd almost certainly run into a situation where more than one array is being used at the same time (simultaneous access), and that will slow you down (heads moving like mad).

    Best to keep scratch on a separate disks (single disk or RAID) than your working data as it prevents this.

    Worth mentioning, as I expect you'd be disappointed when you run into the simultaneous access issue (performance can drop to less than a single disk).
     
  17. khollister macrumors 6502a

    khollister

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    #17
    Yup agree completely. In my case, the pair of disks that host the 2 RAID stripes have no other data that is involved in the operations. One RAID is my CS5/NX2 scratch, the other is my sample library when doing music. Neither my photo library nor my MIDI/audio tracks are held on the remaining partitions on those 2 drives, thus avoiding contention.

    You would be better off to use a single 3TB drive for your data and a separate small SSD for scratch. BTW, not sure how much RAM you have nor how large your typical PS documents are, but if you are using CS5 you are much better served buying RAM and staying off the scratch disk completely.

    I typically work with 12-16 MP images with < 10-15 layers, and never hit the scratch disk at all with 12 GB RAM. I only bothered because NX2 is still 32 bit and can only address 4GB RAM, so it uses the disk constantly.

    On the other hand if you are using 35-50 MP medium-format images with dozens of layers, you might care about the scratch disk.

    NX2 is Nikon CaptureNX2 - Nikon's RAW editing software for Nikon DSLR's
     
  18. kalex macrumors 65816

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    #18
    Definitely raid them. There is a reason why they are called DeathStars
     
  19. And1ss macrumors 6502a

    And1ss

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    #19
    hahaha
     
  20. sparkie7, Aug 31, 2011
    Last edited: Aug 31, 2011

    sparkie7 thread starter macrumors 68000

    sparkie7

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    Oct 17, 2008
    #20
    Ok thanks for the heads up

    Thank you again for your advice.

    My set up includes:

    Mac Pro 3,1 (2008, 2.8 x 8 core)
    16 GB RAM (4 x 4GB)
    1x ATI 3870
    1x ATI 4870
    3x 30"  Cinema displays

    DRIVES
    1x Vertex 250 SSD [Boot and Apps, & current working files]
    1x WD 320 HDD [Came standard with Mac Pro, partitioned into 2 volumes: 1 for Vertex Clone back up with CCC and remaining 58GB on volume 2 as an alternate boot drive specifically for starting up on to clone the Vertex onto the WD partition 1]
    A bunch of externals for back ups/storage/data movement - 3x 1TB WD's, 1x 500GB WD, 1x G-Tech Mini 500GB
    2x 3TB Hitachi Deskstar's internals 7200RPM HDD's [ just arrived, waiting allocation ]

    I use Photoshop (CS5, CS3), Indesign, Lightroom, Illustrator, planning on using 3D apps, some video as well. I work with similar files, 35MB+ files usually singly. Other times multiple in layers or panoramic.

    I have 16GB RAM installed which is probably adequate for just CS5 but I usually typically have multiple apps open on any project, usually about 6+: eg. CS5, LR, Indesign, Word, Illustrator, Acrobat, Safari, Mail, Suitcase, iTunes, Calendar, Textedit, Preview.. so the RAM gets used up fast esp on big CS5 and Indesign documents. I have actually paged out a few times maxing out the 16GB.

    As for using an SSD as scratch, I just have the one SSD - the Vertex 250GB which is a couple of years old now. Its formatted at 238GB, 125GB is used with 113 available, so just under half empty. I could use a portion of this available space as a scratch disk, but concerned as its an older SSD whether it would wear it out. Your thoughts/advice on this option?

    Your suggestion about more internal RAM is quite a good one which I had not really entertained (as I wanted to avoid investing in old tech, which can't be utilized on newer equipment down the track). I have 4 slots left so could get 2 more 4GB DIMMS but need to check pricing, I'm sure they have come down from 2yrs ago when I bought mine which were pricey.

    As to getting a smaller SSD for dedicated scratch, the only problem is I now have 4 drives and all the Mac Pros bays are now used up. Unless I get a tray to use the unused 2nd optical bay eg MaxConnect or Pro Caddy, but want to avoid this if possible as I don't think I have any spare power outputs left as I used one of the spare ones from the optical bay to power the ATI 4870. Which means there may not be any power outputs left for additional drives.

    So it sounds like the overall advice is just to use the two 3TB Hitachi's as data storage and back ups?
     
  21. khollister macrumors 6502a

    khollister

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    #21
    Ah - additional info is a big help. Here is what I would do ...

    Remove the original 320GB (more on that later) and replace it with a 2nd small SSD for scratch purposes. Install the two 3TB Hitachis - one for data/home, etc. and one for Time Machine.

    Get an inexpensive eSATA card (OWC has one for $49 that is fine) and one of their Voyager bare drive docks. Take all of your present external drives and strip the drives from the cases. Get some inexpensive storage boxes from newegg to hold the bare drives. Use those (and the 320 you removed) as your pool of drives for backup using CCC. Eliminates the rats nest of cables and drive enclosures with separate boxes.

    Time Machine is important as an archive - protects you against mistakes (delete a file, etc.) as well as provides protection against a drive failure. The external backups are protection against drive failure(s) as well as fire/theft/flood/lightning strike/etc.
     
  22. sparkie7 thread starter macrumors 68000

    sparkie7

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    Oct 17, 2008
    #22
    Thanks, def worth considering.

    Are you suggesting I take all my disks from the external enclosures and housing them in one larger multiple drive enclosure?

    The only reason I prefer to keep them external is so I can have these back ups offsite. And also what would I do with all the spare used enclosures?

    I think I have 2 hidden SATA connections in the Mac Pro 2008. Could I not connect a couple more drives in the spare optical bay. Does anyone know what cables I need to connect them up and do I need power cables as well? This is where I could install the smaller scratch SSD.
     
  23. DustinT macrumors 68000

    DustinT

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    Feb 26, 2011
    #23
    You are overcomplicated this quite badly. What you really want to do is return those drives and get one SSD. You will not wear it out and it will be an order of magnitude faster than that partitioning nightmare described above. And lets not even talk about how you'd do data recovery on something like that. Raid 0 is a horrible solution for desktop users and should almost never be recommended.
     
  24. sparkie7 thread starter macrumors 68000

    sparkie7

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    #24
    I need the 3TB storage capacity.

    How about I RAID 0 both drives at 1TB volumes through out. I get double the performance whilst still getting the capacity. And back up regularly to mitigate the risk factor. Will this still pose simultaneous access issues?
     
  25. khollister macrumors 6502a

    khollister

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    #25
    No - I am suggesting this: http://eshop.macsales.com/shop/NewerTech/Voyager/Hard_Drive_Dock

    It lets you use bare SATA drives - no other enclosure required. You get some bare drive plastic storage boxes from Newegg for about $5 ea and you are set. Give away or throw away all the other enclosures.
     

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