Seagate Hybrid HD in Mac Pro?

Discussion in 'Mac Pro' started by JesterJJZ, Jun 12, 2010.

  1. JesterJJZ macrumors 68020

    JesterJJZ

    Joined:
    Jul 21, 2004
    #1
    Anyone put one of these in a Mac Pro? I was considering upgrading my 2006 MP with a SSD but I'm considering one of these for now. I'll probably be getting a new MP within the next couple years so I don't want to go upgrade crazy. Anyone have any experience with one of these? I know the initial batch had noise issues, but it looks like they have been worked out.

    http://www.newegg.com/Product/Product.aspx?Item=N82E16822148591
     
  2. strausd macrumors 68030

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    Texas
    #2
    I have not tried it but I have read a few reviews saying they work fine for Mac. The thing that worries me is that what happens if you open certain applications or files so much that it takes off your boot files from the NAND? Would that keep those applications and files on the NAND and put the boot files on the mechanical part? If so, then boot times would go back to being the same as a 100% mechanical drive.
     
  3. JesterJJZ thread starter macrumors 68020

    JesterJJZ

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    Jul 21, 2004
    #3
    Boot times don't really bother me, I reboot my machine maybe once or twice a month. I think it constantly refreshes the SDD section to keep the most used files on there so there shouldn't be any issues. From what I read it takes a few reboots for the drive to learn what files you use the most.
     
  4. duky macrumors 6502

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    North Carolina
    #4
    If you have a Mac Pro with 16GB of RAM you sound like a "go all out" kind of person who doesn't compromise and probably is a power user; for that reason, I think you should go full on and get an SSD that will be a ton better for you.
     
  5. JesterJJZ thread starter macrumors 68020

    JesterJJZ

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    #5
    While I guess I am a "power user" I just want to prolong my system as long as I can without going crazy with upgrades. I'm hoping to hold out until Sandybridge for my next upgrade. I guess my alternative would just be an 80gig Intel SSD.
     
  6. duky macrumors 6502

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    #6
    That, or I'd say the 160 which I think is better value considering it has faster speeds. Then again with a Mac Pro you have multiple bays so the size of one of the hard drives doesn't matter very much does it?
     
  7. JesterJJZ thread starter macrumors 68020

    JesterJJZ

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    #7
    Well, right now I have all 4 bays full plus one in the optical! But my point is I don't want to put much more money into my current setup. When the next Final Cut update comes out I'll be doing a full system reinstall so that's when I plan on just getting a new drive for boot.
     
  8. gglockner macrumors 6502

    gglockner

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    #8
    I'm on the fence between an Intel 160GB SSD and the Seagate Momentus XT Hybrid HD. I'm leaning towards a pair of Seagates running in RAID-0. Should give great performance, maybe not quite as fast as the Intel but I won't have to worry about the issues of write speed slowdown. The OWC Mercury SSD sounds great but it's more than I want to spend, especially for a no-name drive.

    I'm not making any decisions until I return from some travel, but I'm leaning toward the Momentus XT.
     
  9. deconstruct60 macrumors 604

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    Mar 10, 2009
    #9
    This all somewhat depends upon what the percentage free space is in your file system and the size of the files you manipulate on average. Also depends if you open the same files repetitively.

    One reason to have 5 drives is to stripe wide with RAID-0. In a quest for speed, only use the outer sectors of the drives and read/write in parallel to 2,3,4 drives. That leaves numerous drives with lots of empty space. Space is not a topmost or secondary constraint.

    Another reason to have 5 drives is that the percentage free space on your drives is low. You have lots of data to store. Also want speed, but cannot ignore the question of space and have a budget. ( can do all kinds of things if budget is infinite. In reality most folks have a fixed budget to work with. Once trying to satifying 1,2, or 3 constraints the same time need to work through compromises.)


    For example if have two 320GB drives in a raid 0 set up holding 400-500GB of data now, you can just swamp out those two and put in two XTs. That would be an example of the second case. If had three 320GB drives in raid-0 holding 120-320GB of data that would be an example of the first.
    The extreme case of only storing 120GB ("wasting" 100's of GB of space) is a good candidate to go to single SSD drive.


    The problem that hybrid drives primarily address is that hard drive cache sizes have not kept up with the increase in storage. If you look back hard drive caches have gone from 512MB to 1MB ... to 32 MB . Because there is high pressure to keep hard drive prices down, the memory caches have lagged behind. In fact the percentage cached has gone backwards sometimes. A drive cache stuck at 32MB but the platter storage going from 500GB to 1TB. As the percentage drops the cache effectiveness drops. Down significantly below 1% not really going to have much of an impact except special corner cases (e.g, 32MB/500,000MB ==> 0.0064% theoretical max amount cached).


    With a 4GB NAND flash cache and relatively inexpensive flash controller can give the hard drive a more effective cache. (4GB/500GB 0.8% theoretical max cached. 4GB/320GB 1.3% . 4GB/250GB 1.6%). Additionally at 4GB, the flash cache can be bigger than the file buffer cache that Mac OS X uses also or can cache with different time perspective. So, if as part of your workflow you open the same large files every day then the new cache will pay off. (e.g., some apps always open every day. or some project file open close every day for several days.) If you always open/create new large files once and then rarely circle back to them after several hours then it won't as much.


    Putting these in a RAID-0 is going to be more effective when the logical volume is pulling the same data repetitively. The XT drives are faster than other 7200 drives on average, but with RAID-0 hiding some of the latency by doing things in parallel not necessarily going to get a big "bang for the buck" bump in substituting them.
     
  10. strausd macrumors 68030

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    #10
    If you are creating and opening many files all the time, will it know to keep the boot files on the NAND for fast startup?
     
  11. gglockner macrumors 6502

    gglockner

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    #11
    I think the drive controller looks at what is used most often and puts that on the flash. If you boot frequently, then the bootup information is stored on the flash. If you open Photoshop frequently, then its files are stored on the flash.

    Then again, why are you booting a Mac frequently? It's not Windows, after all. :p
     
  12. deconstruct60 macrumors 604

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    Mar 10, 2009
    #12
    Even Windows... why? Sleep/Hibernate works on it also. A forced reboot several times a day is indicative of there being something broken or have an abnormal workflow process even on Windows.


    For better or worse, it is also lowest common denominator benchmark task. Everyone boots their computer. Not necessary as part of getting work done or often but it is a highly shared task that is extremely easy to measure.

    Clearly worse was the earlier attempts by Intel/Microsoft to just primarily target boot time files with hybrid flash storage. Not all that shocking that those efforts failed. That's goofy. Really not a task want folks to do alot. Also the cache is so small really want it to be able to float to whatever the hotspot is. Looks like it assumes that the OS file cache will pick up the slack once booted. However, again it should be an issue of how high a percentage
    can put into the cache.
     
  13. strausd macrumors 68030

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    #13
    With my MacBook Pro I generally turn it off when I go to sleep and when I'm out of town.
     
  14. strausd macrumors 68030

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    #14
    If Seagate's algorithm is constantly putting things on and off the 4GB SSD, wouldn't that make the SSD part of the drive degrade much faster?
     
  15. deconstruct60 macrumors 604

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    Mar 10, 2009
    #15
    It can be an 8GB part where they are using 4GB for wear leveling (i.e., rated at 4GB but really 8GB of raw space back there) . You are also assuming that what is read most often off the hard drive changes substantially from day to day. The caching update algorithm can have a time horizon component it to it. It doesn't have to have a "small, narrow" cache window if going to use RAM to do that. It can have a "wider" window than the RAM cache of what connotes frequent (i.e., have to see it 3, 4 times if free space is relatively small) . In fact, would be better if it does have a substantially different window than the RAM cache window.

    It is not the constantly reading/writing it is what fraction of the writing to the total capacity of the drive and the amount of "free space".
     

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