My SSD is external...permanently

Discussion in 'Mac Pro' started by trankdart, Sep 6, 2010.

  1. trankdart macrumors member

    Joined:
    Jul 28, 2010
    Location:
    Los Angeles, CA, USA
    #1
    i have a 256GB Patriot Torqx M28 SSD that is the Applications directory for my new MP hexacore via a symlink. It also holds a lot of music sample libraries but it's nowhere near full and probably never will be. It was too expensive. I do not have the OS on it and don't want the OS on it.

    It is not in an internal HD bay or the spare optical bay (of which there isn't one).

    It is in a Wiebetech ToughTech 2.5" external enclosure attached to a HighPoint 4-port eSATA-3 6GB/s 4-lane PCIe 2.0 RAID card.

    One of the other eSATA ports on the same card connects an external Firmtek 5-bay HDD enclosure with a port multiplier and 5 1.5TB WD Black drives configured as a RAID 5. The other two eSATA ports are vacant.

    I have the little 5-volt wall wart for the external eSATA enclosure plugged into the same battery UPS that the computer, monitor and RAID enclosure are using (I only have one 30" ACD monitor), so if the power fails my Applications don't go away faster than the rest of the system.

    A Chronosync job syncs the SSD with a directory called /NOTApplications on my 2TB system drive every other day, so if the SSD ever fails I can boot in with a DVD or Target mode and have my applications directory back, at least for troubleshooting work, by changing the name of that one backup directory.

    The punch line is this: I notice that VirtualRain posted a somewhat elaborate procedure for restoring the speed of an internal SSD. That post was a valuable service for which many are grateful (including me, I downloaded that ISO and I'm sure it will come in handy).

    But with my approach, if I want to restore the speed of the SSD I shut down my Mac, take my external SSD enclosure and plug it into the eSATA port on my Windows 7 laptop, reformat it to NTFS and TRIM it to empty in about 10 seconds. Then I bring it back to the MP, reinitialize it and copy the backup directory back onto the SSD. No sophistication required. I had the RAID card and the RAID enclosure anyway...my only extra dollar cost for doing it this way was the $80 wiebetech enclosure.

    I'm not in the least making this as a recommendation for others to adopt. Just posting the info FYI. The performance is fine for me.
     
  2. Transporteur macrumors 68030

    Joined:
    Nov 30, 2008
    Location:
    UK
    #2
    You've got your apps but not the OS on the SSD?
    I seriously don't get it... :confused:
     
  3. kirreip macrumors regular

    Joined:
    Feb 11, 2009
    #3
    Exactly. Where is your system then? On another SSD?
     
  4. trankdart thread starter macrumors member

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    Jul 28, 2010
    Location:
    Los Angeles, CA, USA
    #4
    I have the OS on the system HD in bay 1 just like any stock setup. The only difference is the /Applications directory on that drive isn't what it usually is. Instead, it's a symbolic link

    ln -s /Volumes/SSD-For-Apps/Applications /Applications

    Now all the apps get installed on the SSD but the system ("/System" and so forth) remains where it always is.

    The reasons are:

    1) I don't want to have the OS on an external drive for obvious reasons.

    2) Apart from a reduced boot time, once you're booted much of the OS code you're going to need hangs out in memory. Therefor disk access time isn't such a big factor. I don't boot that often, my system runs for days or weeks. I think once you're booted, most of the speed advantage of an SSD comes from launching applications or accessing large databases or files.

    Anyway, i'm happy with the way my setup works.

    By the way, another reason this is a "beta" setup is that your have to get permissions and ACL's on everything just right, or some important applications (like Premiere Pro and After Effects and Cubase 5) get confused during installation. I have communicated to several software vendors that their installers have subtle bugs when they run into a symbolic link where the /Applications folder should be. But this is relatively rare: most App installers just follow the link and do the right thing.
     
  5. Inconsequential macrumors 68000

    Joined:
    Sep 12, 2007
    #5
    I have to echo the comments above, it seems like a pointless exercise, esp as you've demonstrated some apps fall over because of the symbolic link.

    I'd put the 256Gb in bay 1/lower 5.25" bay and have it like that :confused:

    Just seems alot of faffing to be honest :/
     
  6. trankdart thread starter macrumors member

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    Jul 28, 2010
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    Los Angeles, CA, USA
    #6
    No problem, as I said, I'm certainly not trying to sell it to anybody; just reporting what I did. As far as pointless, if I notice a useful speed improvement in app launching all day every day, that seems to me like there's a point to it. :)

    A few apps do fall over temporarily during installation. It's all fixable with a few keystrokes and my apps all work fine. But yes, those few keystrokes are indeed something that most people would not want to and should not have to deal with.

    I have two optical drives and I use all 4 bays drive bays (plus 5 external HDD's), so this is a solution that works well for me. YMMV.
     
  7. VirtualRain macrumors 603

    VirtualRain

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    Aug 1, 2008
    Location:
    Vancouver, BC
    #7
    I'm not sure the benefits of being able to do the occasional secure erase / trim is worth the hassle of having your OS on a different HD. It's not really saving you much hassle... that's for sure. Also, the performance on these drives isn't that fragile that you need to do this very often. As other's have said, I would just put everything on the SSD and be done with it.
     
  8. Loa macrumors 65816

    Loa

    Joined:
    May 5, 2003
    Location:
    Québec
    #8
    Performance is a relative term, and putting a "for me" doesn't really help anyone. Regardless of what others think, you should at least "try" having the optimal SSD+OS set-up once.

    Just once.

    Then revert to your current set-up if you want to.

    Loa
     
  9. cnstoll macrumors 6502

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    Aug 29, 2010
    #9
    Famous last words.
     
  10. goMac macrumors 603

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    Apr 15, 2004
    #10
    Actually, the exact opposite is true. Applications hang around in memory constantly once they are booted. Meantime, stuff from the system is constantly being shuffled around well after boot. You have the virtual memory page files and frameworks and libraries constantly being shuffled in and out of memory, with the virtual memory page files being the most important performance drag on your system, much much much higher than applications. The virtual memory swap files are a huge huge database tens of gigs large sitting on your boot drive.

    I'd reconsider your setup if I were you...
     
  11. milo macrumors 604

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    Sep 23, 2003
    #11
    If you are paging memory in and out all the time, it means you don't have enough memory. And in such a situation, adding more memory makes way more sense than SSD. Once you have enough memory, SSD is great to have as well, but loading in and out VM page files all day is a really poor use of an SSD drive.
     
  12. trankdart thread starter macrumors member

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    Jul 28, 2010
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    Los Angeles, CA, USA
    #12
    Correct. There is "virtually" no outbound paging/swapping activity on my 24GB machine, and most of the page-ins happen at boot time and application launch. What my Activity Monitor says right now, after my machine was last booted on Thursday, is

    VM Size: 212.9 GB
    Page Ins: 1.11 GB
    Swap Outs: 0 bytes
    Swap Used: 0 bytes

    However it may also be true that a lot of the application code, to the extent that it's shared among applications, tends to hang around in memory and not get paged in either.

    I don't know what Mac OS's policy is in terms of keeping unreferenced code pages around, whether it just forgets about them as soon as they're unreferenced or leaves them in memory based on some LRU principle...too long since I looked at stuff like that. But what it definitely doesn't do is page them out into the swap file.
     
  13. goMac macrumors 603

    Joined:
    Apr 15, 2004
    #13
    That's actually not true... As discussed in another thread recently the system will automatically swap in and out inactive memory, regardless of how much RAM you have. Not to mention, all of your memory is automatically mirrored in swap files, even if it's active in memory.

    Applications really only load things at launch, including databases. These are all loaded into RAM at launch, in which case your swap file is holding all the contents that got loaded by your application, putting all the pressure on swap, even for application resources. There are exceptions for things like games, that might stream assets at runtime. But in general, applications cache most everything in RAM at launch.

    Swap files are really the biggest priority to put on an SSD. The actual applications themselves contain what... 2 to 5 megs of executable code? Not really a big priority compared to what they're likely manipulating in memory.

    Edit: The other thing you'd want to use an SSD folder was if you were working with very large video or photos, in which case I'd keep your documents on SSD.
     
  14. milo macrumors 604

    Joined:
    Sep 23, 2003
    #14
    So if my machine shows a low number for page outs in activity monitor, you're saying it's still doing a ton of swapping?

    And while it may be impossible to avoid all VM page swapping, in general isn't having more memory going to mean less swapping? And isn't less swapping going to be faster for the machine than more swapping, even if it's swapping to a faster drive?
     
  15. trankdart thread starter macrumors member

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    Jul 28, 2010
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    Los Angeles, CA, USA
    #15
    You mean, when I post output from my Activity Monitor that says after five days of use, swap-outs zero and swap used zero, you think either Activity Monitor is wrong, or I'm lying?

    All of your physical memory and then some is mirrored in virtual memory in the sense that disk space is reserved for it. But that doesn't mean that any disk I/O to that swap space is ever actually performed, whatever it says on another thread.

    Let me repeat: after five days of use, swap outs zero, swap used zero. I could post a screen shot, but it would say the same thing, you probably wouldn't believe that either, and if you have a reasonable amount of memory you can see it on your own machine.
     
  16. VirtualRain macrumors 603

    VirtualRain

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    Aug 1, 2008
    Location:
    Vancouver, BC
    #16
    Surely not every OS code library is loaded into memory at boot time? It would definitely make more sense to run the OS on the SSD than not.

    In terms of being able to move your drive to a Windows machine to do a TRIM strikes me as one of those situations where the cure maybe worse than the disease. As far as I can tell, you still have to image, format, reimage your drive which is exactly what you have to do with the technique I outlined, where you don't need to run your OS on a separate drive and use symbolic links.

    However, in the grand scheme of things, it may not make that much difference. Whatever gives you the greatest peace-of-mind and satisfaction. :)
     
  17. goMac macrumors 603

    Joined:
    Apr 15, 2004
    #17
    Well, I have two things to say:
    1) Someone was here the other day with the exact same amount of memory and was getting swapping.
    2) Even if you're not swapping, you're still using virtual memory. No swapping does not mean page files and virtual memory lookup tables are not being written to disk.

    Hell. I haven't run out of memory all day (16 gigs), and I'm seeing plenty of swapping. Swapping is something the system normally does, and even if you don't see swap counts, you're still using virtual memory.

    Virtual memory and swap files are not an optional feature the system uses for when you run out of memory. They are constantly running, and constantly being read and written to by the OS.

    No OS code libraries are loaded at launch. Every time you launch a program, it loads all the libraries all over again for that program. That's why you want to run the OS on an SSD.
     
  18. trankdart thread starter macrumors member

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    Jul 28, 2010
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    Los Angeles, CA, USA
    #18
    Oh. Ok, I think this thread has wandered far enough into neverland. I just wanted to report how I set up my system. As I said in my first post, I'm not proposing anyone else do the same.
     

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