1 2 Previous Next 16 Replies Latest reply: Aug 26, 2009 1:18 AM by KJK555
telon175 Level 1 Level 1 (0 points)
I am thinking of getting a Solid State drive for the OS only.
Problems that may a Solid State drive may have with the OS.
1) Defrag I never thought that Leopard needed to or did Defrag the Drive but a Sales rep for apple at Best buy said he thought that they did once the mac was shut down. This was done he said to make defraging easier were unlike windows you had to tell it to or schedule a time to do it and leave it on.

From what I read you are not suppose to Defrag Solid state drives.
If this is true is ether a way to disable it in the OS and if so is their a way to tell it what drives to not defrag?

2. I also see programs for sale for the Leopard OS that parts of programs that are left over from installs and when you delete something if this is true this is also not good because it will slowly fill up the drive.

3. If any of the issues above are true I hope the is a work around for it or a update to it to correct this. Hard drives have been the bottle Neck for any OS for a long time and these solid State drives even though new tech seem to be the answer for this.

mac Pro, Mac OS X (10.5.8)
  • 1. Re: Solid State Drives on a Mac
    sig Level 8 Level 8 (35,770 points)
    1. The folks at BestBuy know nothing about Macs.
    2. If you wish to delete a program dragging it to the Trash will delete 99% of it. There may be some preference files around but they occupy minimal space. Not an issue. It's very simple to find left over stuff after you trash an app.
    3. None of the issues you propose are germain to solid state drives.
  • 2. Re: Solid State Drives on a Mac
    telon175 Level 1 Level 1 (0 points)
    This guy worked for Apple at Best Buy. I never trusted a Best buy person for advice on a PC/ TV / audio devices ever.
    Best buy has a rather Nice section for Apple products at my location this includes every thing but a Mac pro on display and a Apple sales rep to support it. Or at least he wears shirts with Apple logo and bashes the windows os and the other types of PC's but he may just be some one posing as one
  • 3. Re: Solid State Drives on a Mac
    Scott Radloff Level 6 Level 6 (14,490 points)
    telon175,

    Also, at no time does OS X defragment a drive, either a boot drive or a secondary drive. What is does do is write to drives in a way that reduces fragmentation to an absolute minimum. Because of this, fragmentation rarely becomes an issue for most users, and utilities designed to defrag a drive are not necessary.

    The only real benefit that a solid state drive has over a traditional hard drive at present is durability. There have been no tests that show performance is enhanced by using a solid state drive, nor has it been shown that solid state drives improve battery life (not by any significant amount).

    Scott
  • 4. Re: Solid State Drives on a Mac
    sig Level 8 Level 8 (35,770 points)
    "This guy worked for Apple at Best Buy."

    The guy works for BestBuy not Apple.
  • 5. Re: Solid State Drives on a Mac
    telon175 Level 1 Level 1 (0 points)
    Thanks I would not argue the fact that he works for Best Buy and not Apple.

    But as far as improvements they seems to show more than what you stated.
    Read and right speeds are close much faster than that of a standard sata 3 Hard drive. I have no proof of that being I don't own one but from all I all I read you will see a big deference.
    This is still new and expensive tech and still debating if it is worth the money to buy one at this time while the price is so high per gig of storage.
  • 6. Re: Solid State Drives on a Mac
    jjdemoya Level 1 Level 1 (0 points)
    Dear Scott,

    I am going to have to disagree with you, please refer to this article concerning solid state drives and their performance capabilities.

    http://www.anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3403&p=1
  • 7. Re: Solid State Drives on a Mac
    Michael Superczynski Level 5 Level 5 (7,455 points)
    Performance is most certainly enhanced with an SSD.

    Although I'm relying on my own testing, the fact that there are no moving parts and any part of the SSD can be accessed nearly instantaneously vs. the system having to wait while the hard drive's head is mechanically positioned makes a huge difference in performance.

    I will never go back to a hard drive for my system drive if at all possible.
  • 8. Re: Solid State Drives on a Mac
    Network 23 Level 6 Level 6 (11,695 points)
    Scott Radloff wrote:
    Also, at no time does OS X defragment a drive, either a boot drive or a secondary drive.


    Not true, OS X does automatically defrag files that are 20MB in size and under. But it doesn't do it at shutdown like the Best Buy guy said, instead it's always doing it in the background.

    What is true is that this has nothing to do with solid state drives, since random access is just as fast as sequential.
  • 9. Re: Solid State Drives on a Mac
    KJK555 Level 4 Level 4 (2,895 points)
    Defragging isn't going to destroy data on an ssd, all it does is reduces the life of the drive because
    there are only so many times data can be written to disk before the sectors in question wear out, but
    it is a number much higher than a standard hard drive, I would ignore it for all practical purposes.
    Leopard defrags small files, but it also has a habit of rewriting them in a different spot when it does,
    so the automatic defrag process will have minimum effect on the SSD's life span, in fact it may
    improve the life span of the drive because temp files that are constantly reading and writing to disk
    will be moved occasionally to a new area on the disk instead of wearing out one spot continuously.

    Defragging an SSD has no effect on performance because unlike a standard hard drive there is no
    mechanical parts that need to move from area to area to read data. Data at any location on the drive
    can be read at the same speed, because there are no moving parts.

    So in a nutshell you are burning excess energy worrying about something that doesn't need worrying
    about.

    Kj
  • 10. Re: Solid State Drives on a Mac
    Network 23 Level 6 Level 6 (11,695 points)
    KJK555 wrote:
    so the automatic defrag process will have minimum effect on the SSD's life span, in fact it may
    improve the life span of the drive because temp files that are constantly reading and writing to disk
    will be moved occasionally to a new area on the disk instead of wearing out one spot continuously.


    Even that shouldn't be a problem, if I understand what I've read about SSDs. They are supposed to have "wear-leveling algorithms" that even out where files get written to, to avoid any one spot being worn down unusually prematurely compared to the rest of the drive.
  • 11. Re: Solid State Drives on a Mac
    gumsie Level 4 Level 4 (2,095 points)
    Scott Radloff wrote:
    The only real benefit that a solid state drive has over a traditional hard drive at present is durability.

    Not sure if I'm just being pedantic, but one of the things that kills me is noise. A Mac Pro with four hard drives spinning is a little irritating. I used my friends iMac the other day. Whisper quiet.
  • 12. Re: Solid State Drives on a Mac
    Scott Radloff Level 6 Level 6 (14,490 points)
    Network 23,

    OS X does not defragment files. Never. What it does do is write files to disk such that they never become fragmented in the first place.

    This is a significant difference. In most circumstances, it means that defragmentation is not needed. On the other hand, it also means that there is no accommodation for defragmentation in those rarer cases where it might be needed.

    Scott
  • 13. Re: Solid State Drives on a Mac
    Network 23 Level 6 Level 6 (11,695 points)
    Scott Radloff wrote:
    OS X does not defragment files. Never. What it does do is write files to disk such that they never become fragmented in the first place.


    It does both.

    In addition to numerous citations around the Web of OS X defragmenting files under 20MB,
    http://support.apple.com/kb/HT1375
    says...
    Mac OS X 10.3 Panther can also automatically defragment such slow-growing files. This process is sometimes known as "Hot-File-Adaptive-Clustering."


    Unless you can show that Mac OS X has stopped doing what it did starting in Panther, Apple says it defragments.
  • 14. Re: Solid State Drives on a Mac
    Scott Radloff Level 6 Level 6 (14,490 points)
    Network 23,

    Well, "never" may have been too strong, but I stand by my statement. OS X just doesn't "defragment" in the commonly accepted sense of the word.

    First, it uses "delayed allocation" to reduce the amount- in many cases to zero- of fragmentation that ever occurs.

    Second, it does use "adaptive hot-file clustering," whereby an elite class of the most frequently accessed files are written to the drive's "hot band." The limitation on size is <= 10 MBs (if I am not mistaken), and this does occur dynamically. Since this necessarily eliminate any fragmentation for these files, one could state that dynamic fragmentation is occurring. The amount of data we're talking about here is very small, however, so to classify this as generic "defagmentation" would be a stretch.

    Third, there is one very limited case when a file will actually be rewritten. Several conditions must be met, the most important being that the file in question must have an allocation of over 8 extents. Since this still applies only to files <= 20 MBs, and given the other fragmentation-prevention measures in place, the conditions under which this occurs will be very, very rare. I will grant, however, that in the rare case that these conditions are all met, the file is indeed relocated to an unfagmented allocation when/if it is opened. Yes, this is dynamic defragmentation.

    All this said, "defragmentation" is generally considered to be when a volume is scanned for fragmented file, and those files are all relocated to elimate all fragmentation. This does not occur in OS X.

    Scott
1 2 Previous Next