Should I defrag RAID 0?

Discussion in 'Mac Pro' started by jpine, Aug 6, 2012.

  1. jpine macrumors 6502

    Jun 15, 2007
    I have two Samsung 1TB HDs. I know I should have them set up as a RAID 5 with a controller or whatever those cards are called. However, RAID 0 is the best I can do for right now. Should I defray the drives occasionally or just leave them alone?

  2. hfg macrumors 68040


    Dec 1, 2006
    Cedar Rapids, IA. USA
    I would just leave them alone. I don't think you need to defrag with HFS+ like you did with Windows.

    My 2TB RAID-0 (2 disk) has been running for years and I have had no problems with it.

  3. rantingrich macrumors regular


    Aug 10, 2009
    Southern Illinois
    MORE SSD Info!

    I have been reading on here about some sort of SATA 3 card/controller which one can easily install with RAID 2 SSDS. WHICH WOULD ALMOST double the speed, I think from like 500 to 800-900.

    I am now thinking of getting 2 x 250 gb SSD say from OWC and setting that up for startup and operations and using the apple factory 1TB 7200 for data.

    I know what to diff. is between stripping (SPEED) and mirroring (BACKUP)....

    BUT I want the added speed of a STRIPPED RAID for the SSDs BUT a STRIPPED set up between the 2 RAIDED SSDs to Mirror off to the7200 HD as a BACK UP. IS that possible?

    I guess what I am asking is for FULL BALLS OUT SPEED on the RADIED SSDs but an automatic backup to the 7220 HD

    IS that possible.

    PS.. Can I say BALLS OUT?
  4. deconstruct60 macrumors 604

    Mar 10, 2009
    It depends up the the state of the file system, the size of the files you normally mutate/create , and how full the RAID volume is. Under normal conditions, you should just leave it alone.

    If you create and mutate lots of relatively very large files ( 10's of MB or more ) then you should periodically check. That's a "yellow alert" state. The HFS+ auto defragmentation system avoids 20MB and larger files. So those won't autocorrect over time if not deleted over time.

    If your RAID volume gets tp about 65-75% full and also have the first condition, then that is definitely a "red alert". You need to check more often than above. With lots of free space, there is usually always room for HFS+ to find a large number of sequential blocks to store large files. HFS+ is not designed with volumes filled to the brim in mind (actually no File system likes to be in that state. But HFS+ automatic housekeeping even less so). Small files that may occasionally drifted into "mostly free zone" causing fragmentation but they will be incrementally cleared away. But the incrementally defragmenting system needs room to work in while still "open for business" services files.

    Pragmatically, throwing out large, old "junk" files periodically is better than to run a program to keep reshuffling the deck chairs.
  5. jpine thread starter macrumors 6502

    Jun 15, 2007
    The RAID is used for video capture (and later dumping). The format is usually Apple ProRes or ProRes LT. I do have Drive Genius 3 installed and it has a defrag function. Thanks for the 411. :D
  6. Edie Brickell macrumors member

    Apr 22, 2010
    When you have a large number of files taking longer time to read/write, regularly creating a lot of files like photo editing files (making them smaller and then larger again in size). Fragmented Files can slow down your applications and longer system startup launch. So when your file gets fragmented, it causes problems then defragmentation is a good idea.

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