SSD and 7200 best suggestion to combine?

Discussion in 'Mac Pro' started by clipsedsm95, Jun 30, 2013.

  1. clipsedsm95 macrumors member

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    #1
    Hey guys i am going to be picking up a 2012 mac pro with a GTX680 32GB ram and 250 GB SSD for $1800 I pretty much have to get the SSD so I want to might as well use it but the capacity is no where near enough for me. I am a photographer and I do use external HD's but Im not so fond of putting anything but my RAW files there. Now I have never used RAID personally my self so correct me if I am wrong... Can I RAID 0 250 GB SSD with a 2TB 7200 HD or is there anything you guys might be able to suggest please and thank you!
     
  2. ness96 macrumors member

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    #2
    You might be able to, but it would be a terrible idea. If you combined a 256 GB SSD with a 2TB in a RAID 0 configuration, your total RAID storage space would be 512 GB. You *might* be able to use the idle 1.5 TB as a separate partition, I don't know (but I doubt it).

    Why not use the SSD as-is, purchase another 2TB drive, and then combine the two 2TB drives into a 4TB RAID 0 config? Granted, if you did this you would want to purchase a backup solution as well. In RAID 0, if one drive dies then all your data is lost.

    Or even better, go all out and do a RAID 0+1? 1 SSD + 4 2TB drives :)
     
  3. Dalton63841 macrumors 65816

    Dalton63841

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    #3
    Yea like the other guy said RAID0 would be a terrible idea.

    Personally, I did this with my Macbook Pro, and it works great. Basically it harnesses the fact that Mac is Unix based and mounts /Users on the separate drive. The OS still treats everything as normal, and in fact can't tell the difference outside from the fact that the/Users directory has a drive icon instead of a folder icon(which you can change if it bothers you).

    Added benefit is that if you need to reinstall, you just do an fstab edit, create a new User with the same name as before you reinstalled, and reboot. Then you are right back with your settings and data in tact.
     
  4. slughead macrumors 68040

    slughead

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    #4
    You can't build a RAID per se, but you can use the SSD as a cache for commonly used files stored on the platter drive (which Apple's software will pick for you automatically). Apple calls this a "Fusion Drive."

    You need to do this before you install Mac OS (it'll erase the contents of both drives).
    http://mac.tutsplus.com/tutorials/hardware/build-your-own-fusion-drive/
     
  5. DPUser macrumors 6502a

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    #5
    This.
     
  6. clipsedsm95 thread starter macrumors member

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    #6

    Are you suggesting Something like this? Here I just ran Across this earlier today and didn't realize how seamless it is I might just do this! Thank you for the responses everybody!!
     
  7. Dalton63841 macrumors 65816

    Dalton63841

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    #7
    The tutorial I showed you is similar to that, except you don't have to change your User location in System Preferences, because as far as the OS can tell it's in the same place. It's a lot easier with the tutorial I pointed you to, and the end result is the same.
     
  8. brand macrumors 601

    brand

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    #8
    Its entirely possible to create a RAID0 from a 512GB SSD and a 2TB 7.2K HDD. The array will be the 2 x size of the smallest drive and the speed of the array will be basically limited to 2 x the speed of the fastest drive minus overhead.
     
  9. slughead macrumors 68040

    slughead

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    #9
    I assumed he wanted the drive for its capacity, since he said that 250GB was "no where near" enough. I therefore didn't even think about sacrificing the rest of the space on the 2GB drive (unless that ends up being preserved somehow as another partition--I've never actually done it)
     
  10. brand macrumors 601

    brand

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    #10
    I wouldn't recommend it though since it sacrifices the speed of the SSD and the capacity of the HDD.
     
  11. hfg macrumors 68040

    hfg

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    #11
    There would be absolutely no advantages to RAID-0 with the 2 drives you suggest. :rolleyes:

    I would create a DIY "Fusion" drive using the 256GB SSD and the 2TB hard disk for SSD performance and hard disk capacity. Or keep them separate if you desire to try to manage them yourself. I would recommend the Fusion. :)

    In my Mac Pro my OS X drive is a Fusion array with a 512GB SSD and half of a 4TB hard disk. I do have a PCIe card (SATA-III) with a pair of 512GB SSDs in RAID-0 where I keep my photo library as well for maximum speed with the large photo files.
     
  12. slughead macrumors 68040

    slughead

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    #12
    I'm doing it the homebuilt PC I just made (it's called "SRT" on the PC side)... It's absolutely amazing.
     
  13. brand macrumors 601

    brand

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    #13
    Intel Smart Response Technology is not the same thing as a Fusion Drive. With Intel SRT the frequently accessed files kept on the SSD still reside on the HDD. With Apple's Fusion Drive the frequently accessed files are only kept on the the SSD and the less frequently accessed files are kept on the HDD.
     
  14. slughead macrumors 68040

    slughead

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    #14
    I was not aware of that! So effectively, SRT has a "backup" of the SSD cache and Fusion doesn't. Fusion therefore allows for more space. Like some weird RAID SPAN.
     
  15. brand macrumors 601

    brand

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    #15
    That is basically correct although I wouldn't call it a backup. With SRT the SSD is technically a cache. With Fusion the frequently used files are constantly being moved between the drives. I also wouldn't call Fusion a RAID span but I guess that term could be used to explain it to a layman.
     
  16. hfg macrumors 68040

    hfg

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    #16
    Fusion is a form of "tiered storage" and manages at the block level, even lower than whole files. The advantage is that frequently accessed blocks are maintained on the SSD, while less frequently (or never) blocks (and unused files, apps, data, etc) are moved to the hard disk. This is all done by OS X, the user simply sees a normal OS X type drive configuration, and nothing special needs be done by the user to maintain the high perrformance aspects of the drive.

    It seems to work quite well, although a 100% SSD would be slightly faster at times, the cost would be many times that of the Fusion compromise. Apple ships Fusion drive systems with a small 128GB SSD, which I think is too small, especially with large 3TB optional drives. I have found that 256GB or 512GB SSDs combined with 2TB to 4TB hard disks work very well for my systems and workflow.

    I have even had good results with RAID-0 SSDs and RAID-0 hard disks combined in a Fusion array, but it is tricky to get it built and loaded with OS X.


    -howard
     
  17. derbothaus macrumors 601

    derbothaus

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    #17
    I symlink portions of my home directory so I know where stuff is in the event of a single drive failure. I have messed with Fusion but ultimately no faster just twice as likely to fail. ymmv.
     
  18. hfg macrumors 68040

    hfg

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    #18
    That's really not true in practice, although you will read the same message over and over on these forums. You are no better off if your single drive fails than you are if one of a multi drive (Fusion, RAID, etc) drive fails.

    You simply replace the failed drive and restore from your backup.

    Do you have a lot of drive failures (not counting the small external drives which usually die from over-heating due to inadequate cooling)?

    Or are you saying that your system doesn't need a backup?

    Fusion drives are considerably faster in normal use. Perhaps yours wasn't created properly if you didn't notice a speed advantage (and you would notice it if it was running properly). Depending on how you initially load it, it may take awhile for the Fusion drive algorithms to adjust the storage to your personal usage.

    Since the OP appears to be a new Mac user ... using symlinks is probably not the best way for him to start out. I use them too, but a simple OS X environment is probably better for a new user.

    -howard
     
  19. slughead macrumors 68040

    slughead

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    #19
    Is RAID just uncool now? Are we relegated to time machine?

    What I can see as the best solution is a RAID 1 with a couple (or more) platter drives and SRT (SSD caching) on top of that.

    SRT is very nearly as fast as a straight SSD anyway, and therefore just as fast as Fusion. With a RAID-1, you have redundancy and robustness. SSD fails? Just run without SRT while you wait for replacement. Platter drive fails? Just swap it out and rebuild your RAID1 when your system is idle.
     
  20. brand macrumors 601

    brand

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    #20
    SRT is not nearly as fast as a standalone SSD though. Since the SSD in an SRT setup is just a cache drive at some point it is limited by how fast it can write data to the HDD. Additionally the portion of an SSD that is dedicated to SRT can be no larger than 64GB.
     
  21. hfg macrumors 68040

    hfg

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    #21
    Nothing wrong with RAID-0 for me. I have been using RAID-0 in almost every computer I have owned/built over the last decade or so (ever since disk drives became cheap enough to afford to buy 2 or more at a time, instead of just 1 :) )

    RAID-1 is dangerous for users who think it is a backup as you indicated above. If you create a corrupt file or folder, you now have an exact copy of the corruption. RAID-1 is useful if you can't tolerate ANY down time in the event of drive failure ... but we all aren't running real-time banking systems.

    SRT isn't as fast as Fusion with normal usage, since it has a limited SSD component and doesn't adapt to your usage over time. It simply caches the small amount of storage you recently used more than once. Fusion will keep your entire environment of repeatedly used apps, data, and library files on the SSD for fast use, and does so with way better granularity than you could possibly do with symlinks.
     
  22. derbothaus macrumors 601

    derbothaus

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    #22
    Thank you. I'm out...

    Kidding.
    So even though your response was not needed and an attempt at passive superiority (I could be wrong).

    It is faster to image half the contents than the entirety. If I have an external with similar image I can link up the data portion if it was not the failed drive and off I go. Alternately I can keep working in the boot volume while I restore the data drive if it was the dead member. So it is slightly beneficial. If not to you then fine. Someone else may see this benefit.
    I can't tell the difference from a properly (love the superiority assumptions all over this place) configured Fusion drive and my sym links to velociraptor. I only link HDD to movies, music and docs, and Steam games.

    And to answer the veiled question yes, I have zero backups. Don't need 'em. They are useless and a conspiracy. I do have a RAID5 I use so that is close to the same thing, right?
    Please read in this enormous sarcasm.
     
  23. ssls6 macrumors 6502a

    ssls6

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    #23
    Sounds like a nice setup. Put your OS & apps & most user stuff on the SSD. Use the HDD for data files. By far the best setup.
     
  24. hfg macrumors 68040

    hfg

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    #24
    Wow ... you don't even know me and you have attempted to profile my whole personality in one post. Impressive! :cool: I love sarcasm, so if that is your thing, keep it up ... practice makes perfect! If you read my other posts here, you will find that I genuinely try to help people in areas I do have experience ... I seldom resort to any form of sarcasm or "superiority complex", although I am tempted sometimes. But I digress...

    I was simply trying to give some advice to the OP.

    I currently have my Mac Pro dual boot OS X for perceived speed testing:
    1) bootable RAID-0 SSD on SATA-III PCIe with symlinks to more static data on HD (yes, I do use them too).
    2) bootable single SSD in Fusion, having also testing separate SSD and HD

    Yes, for large files (video, movies, photo), they will load at hard disk speeds since that is where Fusion has them stored. I put mine on a static hard disk partition not managed by the Fusion algorithms. If I wanted more speed, I would put them on a 2 or 3 disk RAID-0, but not needed for videos. Or, if they fit, on a RAID-0 SSD (I use a 1TB one for current photo library files).

    If you use Migration Assistant to initially load your Fusion drive, OS X stuff (apps, libraries, etc.) will load first and already be on the SSD when the user starts using it. However, if you clone your system (with CCC or other), you will probably load the Fusion drive alphabetically, and may have OS X components initially on the hard drive, which will take some usage time for all to migrate over to the SSD.

    Glad you keep backups ... it seems many posters here who are the most worried about multi-drive disk failures, don't keep any backup at all. I find that really ironic!


    -howard
     
  25. derbothaus macrumors 601

    derbothaus

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    #25
    hfg is pure class. No attacks. I misunderstood your tone as it is hot as balls in the pacNW.
     

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