OWC Raid-Ready-Enhanced SSDs and difference?

Discussion in 'Mac Pro' started by WardC, Oct 8, 2010.

  1. WardC macrumors 68030

    WardC

    Joined:
    Oct 17, 2007
    Location:
    Fort Worth, TX
    #1
    Does anybody know anything about the OWC Raid-Ready-Enhanced SSDs and the difference in using these for a RAID 0 vs. using the Standard Mercury Pro Extreme SSDs that are not RAID-enhanced? The RRE drives cost a bit more and I don't know exactly what benefits you would get running a RAID 0 (two or three drive RAID 0) with the RRE drives versus the standard SSD drives? Anybody know anything regarding this?

    Thanks.
     
  2. Honumaui macrumors 6502a

    Joined:
    Apr 18, 2008
    #2
    lot of speculation ? and a lot of it wont matter it might matter it will matter ?


    I guess we will see

    I have two RE and 3 regular ? test wise ? cant see the difference

    also you can raid the non RE ones no problem :)

    I got them for that extra bit of over provisioning as I am not going to fill them over %50 and to me 120 or 100 gig did not matter so I was thinking might as well get the RE :)

    but for my other use raid 0 cache I am using the normal ones ;)
     
  3. noire anqa macrumors regular

    Joined:
    Aug 20, 2010
    #3
    At a guess i would say greater over-provisioning to compensate for the increased wear, and a higher quality of flash chip to maximise life expectancy.

    i highly doubt it's anything to do with speed, RE HDDs have increased durability provisions to compensate for the extra strain put on them. with an SSD the strain is a greater issue, if you were to use a RAID of HDDs id say you might be able to get away with standard drives (depending on your usage). for SSDs however id go for the REs.
     
  4. deconstruct60 macrumors 604

    Joined:
    Mar 10, 2009
    #4
    In a general sense, it is the same distinction that "RAID Enchanced" hard drive have. They are configured for higher than average I/O workload environments compared to the more mainstream. If you put them through a tougher beating then they can take it better. Typically increasing the bandwidth increases the amount and "breadth" of data passing through the storage system.

    Primarily what they have is a higher bigger "over provisioning" budget.
    It is mentioned in the graphic on this page:

    http://eshop.macsales.com/shop/internal_storage/Mercury_Extreme_SSD_Sandforce

    Pro -- 7%
    Pro RE -- 28%

    Simply put, you are buying more Flash storage. ( the controller manages its usage, but it will get used over the long term under demanding conditions. )

    The difference means, if the garbage collection algorithms fall behind the curve, the RE version has more room to handle a longer write burst. Similarly, if "burn out" 6-7% of drive in 2 years from writing to the same spot too much then the RE can keep going whereas the Pro drive is spent.


    If your RAIDing primarily to read only a constant set of data then there is largely no difference. If write workload is increasing as fast a read workload and want to RAID just as much to keep up with writes.... then 28% over provision makes a difference.

    Look at your Read/Write ratios. If write is a very low percentage then may be a toss up. (getting somewhat better wear protection by going RAID 0 since distributing the writes ). if the read/write precentage is 50/50 then RE would be a go. If the write percentage is over 80 and TBs per month or year then may want to pass on both. ( NOTE: I'm sure folks are going to roll in here and claim Flash SSD drives are extremely delicate flowers and try to write them in any non trivial amount they will collapse into a heap... that's not really true if buy a modern, decent one. The over provisioning controls the issue to a large extent for a extremely wide variety of workloads. )

    P.S. On younger drives it is doubtful would see a difference unless composed an explicit test to precisely engage the respective over provision capacities. Over time if abuse the drives it should more easily show up. Mainly on differences in write speed.
     
  5. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #5
    The RE versions are clearly stated that they've additional overprovisioning than the Pro versions, and a longer warranty (5 years vs. 3).

    As per bandwidth (improved IOPS), it's possible. Perhaps the Pro uses the SF-1500 Sandforce controller, and the RE either SF-2500/2600 (as well as firmware tweaks). Not sure if there's enough cost difference between the models to manage it though (40GB Pro vs. 50GB RE; can't find pricing on the SF1500 and SF2500/ 2600 controllers).
     
  6. alphaod macrumors Core

    alphaod

    Joined:
    Feb 9, 2008
    Location:
    NYC
    #6
    If you get the regular (non-RE) version, I've been told not to use 100% of the capacity and use say only 70% at most and I should be fine with provisioning issues.
     

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