SAS drives and Raid

Discussion in 'Mac Pro' started by jgbr, Apr 13, 2011.

  1. jgbr macrumors 6502

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    Sep 14, 2007
    #1
    I am considering getting the raid card for the Mac Pro (the Apple one)

    Am i correct in saying that I can buy 4 SAS drives to fit the 4 bays instead and then raid them?
     
  2. alust2013 macrumors 601

    alust2013

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    #2
    nanofrog will probably be here shortly, but from what I have gathered, it's best not to buy Apple's RAID card due to expense and that it isn't too great. I also don't believe you can use SAS drives, as the bays still use standard SATA connectors.
     
  3. Transporteur macrumors 68030

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    UK
    #3
    SAS drives work fine, provided you've got the Apple RAID card.

    If you opt for a third party RAID card (which is what's recommended) you have to use third party drive sleds since the standard bays do not work with third party RAID controllers.
     
  4. jgbr thread starter macrumors 6502

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    Sep 14, 2007
    #4
    I'm just trying to get the right combo for a server thats all,

    backup for users but also speed.
     
  5. jgbr thread starter macrumors 6502

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    Sep 14, 2007
    #5
    so what happens if i get the apple card and then buy 4 scsi cards "of the shelf"

    for my work load im wondering if any benefit of moving from standard SATA to SAS anyway - its just email hosting, database, dhcp stuff really
     
  6. JollyJoeJoe macrumors regular

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    Apr 3, 2011
    #6

    Will using these bay adapters to the backplane limit 6G SATA3 drives to SATA2 3G speeds? Is it possible not to get these bays and use default ones that come with the mac pro and just not use their connectors and instead run mni SAS-4x SATA multiplier and connect to the drives in the bays ? Or is going via the backplane internal channels the only option ?
     
  7. nanofrog macrumors G4

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    May 6, 2008
    #7
    Just sticking to this question and ignoring any other factors, the Apple RAID Pro card does work with SAS disks.

    I finally made it... :p

    The Apple RAID Pro is definitely junk IMO (expensive for a 4 port card that only works with one OS, slow, and still has battery problems).

    A 3rd party alternative offers more value for the money, as well as options, speed, and features (especially for recovery in the case of ATTO or Areca, as both of these keep a copy of the partition tables in the card's firmware - most don't).

    This is the right way to go card wise, and the adapter kit if the disks are to be internal (cheaper than an external enclosure).

    SAS can definitely make a difference in Database usage, as they're designed for higher IOPS than SATA.

    But the specifics will matter. So think of answers for the following questions (may not be all inclusive, but hopefully enough to get started):
    • What are you doing exactly (how much of what's used, ...)?
    • What is the primary configuration/requirements as well as the backup requirements?
    • What is the capacity needed now, and what is your growth rate (figure the system needs to fit your needs for at least 3 years and only add disks and enclosures)?
    • What are your throughput requirements (what you're doing can help, but this really nails it down if you can produce a number)?
    • What is the user count for the database?
    • What is your budget?

    No.

    The limitation will only exist if the SSD's are connected to a SATA II controller (forces the SSD to step down to that spec).

    But if you get a SATA III compliant card (6.0Gb/s - there are both non-RAID and RAID versions from ATTO, RAID only so far from Areca - not sure when they'll get the non-RAID versions out), then the cable's included with that adapter kit will not throttle the speed.
     
  8. Pressure macrumors 68040

    Pressure

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    Denmark
    #8
    Besides Nanofrog's really good advice there is also another option, namely going with the ZFS filesystem, which can make dynamic stripes on its own.

    In this manner you can skip on the expensive RAID-card altogether and opt for more drives and the only filesystem that really offers data integrity.

    You could grab this 12-bay Hot-swappable enclosure for a meager $399.99 and have enough upgrade options down the road.
     
  9. nanofrog macrumors G4

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    May 6, 2008
    #9
    I'm a fan of the ZFS filesystem, as it can offer less expensive alternatives for some (have to make sure the server can handle the overhead, and the user has the technical know how to implement and manage the software, especially if it's via a form of Linux to save on funds).

    There are ready-made solutions out there though (not tried anything out on a Mac, so I don't know if there's issues). But one company that does a decent job of it is Oracle.
     
  10. jgbr thread starter macrumors 6502

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    Sep 14, 2007
    #10
    well the server is only handling a few users files and the rest is email/dhcpgateway etc

    so im really wondering if sas and raid card is worth it? or better soultions? or should i try to distrub the servers files or just slap 4 identical sata drives in etc.
     
  11. nanofrog macrumors G4

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    May 6, 2008
    #11
    If the user count isn't that high (low IOPS), then sticking with SATA could suffice (figure ~90 IOPS for a single SATA disk).

    There's still very little info to go on here, so it's hard to give you solid answers.
     
  12. jgbr thread starter macrumors 6502

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    Sep 14, 2007
    #12
    Well in the end its likely that its going to be internal security, print server, user management and hdcp server and backup.

    no more then 5 users logged in at once.
     
  13. dyn macrumors 68030

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    .nl
    #13
    The 2009 model does mention the use of SAS but the 2010 model only mentions SATA. It might be that since the 2010 model there is no SAS support anymore but I can't find much information about it.

    If by that you mean pissing off everybody than yes, Oracle is very good at that. If you mean decent jobs on software...that is highly debatable (OpenOffice.org, Linux, Solaris, OpenSolaris, btrfs, zfs, etc.).
     
  14. nanofrog macrumors G4

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    May 6, 2008
    #14
    SATA should be fine for that few users.

    In the case of Oracle VM software for storage (meant to be used with Sun's storage appliances), it works when configured properly (the hard part :p).
     
  15. jgbr thread starter macrumors 6502

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    Sep 14, 2007
    #15
    how many users untill saturation point of sata?
     
  16. Transporteur macrumors 68030

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    #16
    Impossible to say given the information you provided.
     
  17. jgbr thread starter macrumors 6502

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    Sep 14, 2007
    #17
    a guess would do

    its 1gb connections on all infrastructure
     
  18. dyn macrumors 68030

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    #18
    That is nowhere near enough info to say anything about when the sata will be saturated. There are an awful lot of things that have an influence on the speed. The server will not be doing just 1 thing but several things at the same time. That adds to the complexity but you can make a good educated guess.
     
  19. nanofrog macrumors G4

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    May 6, 2008
    #19
    As others have mentioned, this isn't possible ATM given the lack of information.

    If you at least posted the IOPS performance data from that server, it would help.
     

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