Mac Pro RAID Card

Discussion in 'Mac Pro' started by alphaod, Aug 2, 2009.

  1. alphaod macrumors Core

    alphaod

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    #1
    I'm thinking of getting the aforementioned card, but have a few questions. Sorry hard to use search on the phone.

    Anyways my proposed set up is 3 drives in RAID 0 and then a separate drive set up as a separate volume used solely for backing up the 3 striped drives. Is this possible with this card?
     
  2. gugucom macrumors 68020

    gugucom

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    #2
    That sounds very reasonable demand, but why do you want a RAID card for that. The Mac Pro chipset will do this with the standard SATA ports. Disk utility will use it to configure your RAID0.
     
  3. alphaod thread starter macrumors Core

    alphaod

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    #3
    I need the best possible performance and I'm not a big fan of software RAID. Also I need the IO requests to be handled in hardware and cache not by the computer processor.

    My proposed solution is 3 300GB WD VelociRaptors in RAID 0 and then a 2TB drive for backup jobs. I'm not sure is software RAID is a good path for that set up.
     
  4. Tesselator macrumors 601

    Tesselator

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    #4
    I think the Software RAID0 is the same or maybe even better performance than Apple's card from what I've read on-line. You'll get more of a speed difference between drive models than you will by adding the Apple Card.

    I think this is true also of ALL cards in the under $500 range as well.
     
  5. alphaod thread starter macrumors Core

    alphaod

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    #5
    Now this may be a tad expensive at the moment, but best case scenario I would get 4 drives in RAID 5. Would software RAID be better for this scenario still? I need the best and most flexible solution.

    I actually already decided if this should work, that I would pay for the card. The important part is that it would need to work. As long as it works I feel it is a good choice. I plan to use the computer for a few years, so as a long term investment it's only a dollar a day assuming the computer gets used for at least 2 years, which shouldn't be an issue since my plan is longer than that.
     
  6. gugucom macrumors 68020

    gugucom

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    #6
    Software Raid is actually misleading. The 5000 and the 5520 Intel Chipsets have a RAID controller included in the hardware which can be addressed by the OS X disk utility. So unless you are disappointed by the functionality will probably find nothing as integrated and closely working with OS X then this thing. I believe RAID5 may be a problem.
     
  7. Tesselator macrumors 601

    Tesselator

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    #7
    If you were comparing RAID5 between "software" and <$500 cards then I guess in many (most/all?) cases it would be the same.

    The "software RAID" in Mac Pro doesn't include RAID5 though. RAID levels 0, 1, 10, and 0+1 are available. RAID0 is better IMO than RAID5 for SOHO uses. It's faster primarily. RAID5 offers redundancy and easy (albeit SLOW!) rebuild and repair in the extremely rare case that one breaks.

    RAID5 is a bit slower than RAID0 but not all that much. Maybe a 20% reduction plus the addition of an extra drive. Meaning a 4-Drive RAID5 is a little slower than a 3-Drive RAID0 for example - all other things being equal.
     
  8. UltraNEO* macrumors 601

    UltraNEO*

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    #8
    Well.. The speed issue is mostly hardware related, nor does it help when Apple's own RAID card is the slowest interface out there, accounting for it's cost. Remember, the entire RAID system will only be as fast as the interface regardless of the type of disks used. It is possible to built a fast RAID5 array using large but expensive SSD's but you'll be restricted in the total size.

    I think there are after-market interface now - they've had plenty of time to make adjustments for the 2009 MacPro.
     
  9. Tesselator macrumors 601

    Tesselator

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    #9
    Yeah, but there's plenty of room (overhead) in all cases (SSD might be an exception in some cases). It ends up being mostly the speed of the hard drives themselves. Until a large cache is introduced - and that's where the over $500 cards come in. No cacheing controller means higher speeds than the HDDs are capable of can not be achieved - only same or slower as in Apple's RAID card. :p

    If it's a 3-Drive RAID0 with drives of 32MB caches then that's a 96MB cache right there. And you can really see how this cache improves performance above the drives abilities (given no cache):

    Notice I'm getting about 600 MB/s across the entire disk surface until the size of the data (at 100 MB) is larger than the combined cache (at 96 MB) and then it starts to drop rapidly as well as the affects of the platter geometry beginning to kick in - Until finally at 300 MB data size the speed becomes more dependent on the write-to-platter-from-interface performance than the write-to-cache-from-interface performance. The speeds of the reads and writes also become more equal as the read-ahead cache is OFF in all of these tests whereas I don't think it's possible to turn off the write cache - or at least not in the software I was using for the tests.
     
  10. UltraNEO* macrumors 601

    UltraNEO*

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    #10
    Off Topic...

    Tesselator, dude. I'm in Tokyo from Friday, just for the weekend. Would you know of any Mac specialists around here, preferably specialising in Raid solutions/interfaces, besides the somewhat limited inventory of the AppleStore in Ginza?

    I'm thinking about getting another raid card for my 2008 MP. The CalDigit one is OK, but you know, it's a little expensive when it comes to outboard storage solutions. Don't get me wrong, those HDElement's look the bomb but at a cost!

    P.S. Has anyone tried using two raid card in their MP??
     
  11. nanofrog macrumors G4

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    #11
    Apple's card is junk, as it's slow, problematic (still having battery problems), expensive, and only works in OS X. :(

    OS X's software RAID support only includes 0/1/10. So if you need any other array type, you will have to get a hardware controller. The cheap side would be Fake RAID, but that still uses the system's resources, so you'd want something with a built in controller and cache, as Tesselator mentioned. Personally, you'd want to look at Areca, or perhaps Highpoint. You can also find cards that can run in multiple OS's, and even boot mulitple OS's (note: Highpoint can only boot one, as you have to swap out the firmware). As you add features, the cost will go up (obviously). Details would help direct you to some cards, if that's the route you still want to go.

    BTW, even with cache, the differences between a hardware implementation of a 3x stripe aren't enough to justify the cost IMO. If you run additional drives, then you're in different circumstances, as you'd have the potential of using more drives (say an 8 port or larger model, and you go beyond the quantity of ports in your system). You also get other array types at your disposal, which allows you to change to meet your future needs. No need to buy anything either (assuming the card hasn't been out grown (port count) or drives (capacity per).

    There were problems with CalDigit when I dealt with it. Too unstable, and the HDElement being locked to the card was too expensive IMO.

    I don't have an MP, but I currently use two cards (Areca ARC-1680ix12 & ARC-1231ML). Each gets a different port ID (machine IP address : port number for browser access), and don't interfere with one another. :)

    If you want to use identical cards, and team them, they were designed to do that as well. But if that's what you where planning on, the CalDigit's mention really wouldn't make any sense. :eek: :p
     
  12. Tesselator macrumors 601

    Tesselator

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    #12
    Sorry UltraNEO, I dunno Tokyo well enough for any advice like that. I think for specialties the internet is the only "customer" option Japan-wide. I guess most guys who have enough experience, or are smart enough, or have the savvy enough to know (or find out) what they're actually talking about don't work in stores.
     
  13. JPamplin macrumors 6502

    JPamplin

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    #13
    If I might chime in, I use 3 Seagate 750s in a RAID0 boot volume that is backed up with a spanned volume in Bay 4 (1TB) and the lower CD bay off an additional SATA port (Bay 5, let's call it).

    I think it runs great, and this in on a 2006 Pro with 2 quad core 5355s - I don't notice that significant of a CPU hit with this setup, really.

    Try it first before you drop the coin on a card - you may be pleasantly surprised.

    JP
     
  14. nanofrog macrumors G4

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    #14
    RAID 0/1 doesn't use much in the way of CPU at all. Using them in conjunction gets a bit higher (1+0 or 10), but it's when you use a parity based array 5/6/50/60 it becomes significant (5 being the mildest, so some software RAID implementations support it). ;)
     
  15. Tesselator macrumors 601

    Tesselator

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    #15

    I don't think it's measurable at all. At least not with any of the tools currently available that I know to use. I guess it's far less than a half of a percent <0.5% of a single core.
     
  16. nanofrog macrumors G4

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    #16
    I've seen 4% under Windows (Vista) for 0/1. Either way, not stressful by any definition. :p
     
  17. Tesselator macrumors 601

    Tesselator

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    #17
    What's the name of the process I would monitor in order to know exactly?
     
  18. nanofrog macrumors G4

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    #18
    It's part of HDTune's results, so you don't have to hunt it down. :)
    But it's iostor.sys IIRC, if you wish to track it down. ;)
     
  19. UltraNEO* macrumors 601

    UltraNEO*

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    #19
    I think your on to something there...

    I don't wanna sound rude cause people work very hard here, however it seem 98% of sales staff in various stores lack any product information, they only know the price, brand and er.. if you lucky, the stock's location!! From all the places I occasionally deal with SofMap has to be the worst store when it comes to product knowledge!!
     
  20. nanofrog macrumors G4

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    #20
    Tesselator's got a good point. Phone calls and emails to sources located on the internet would likely be the best way to go. ;)

    What exactly are you after at this point?
     
  21. UltraNEO* macrumors 601

    UltraNEO*

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    #21
    Eventually I wanna replace that CalDigit cause I think I've hit a wall with it - works flawlessly, does what it says on the box but I need more storage space!! So I'm basically looking for a more flexible interface with a cheaper external expansion path (i didn't think I need it back then) And looking at what Apple has done, it must have an upgrade path so if i later choose to upgrade the system I can migrate the storage system to my next MacPro.

    If it cost as much a VTrak E-Class RAID subsystem, I don't wanna know... cause they're too expensive for my needs.
     
  22. nanofrog macrumors G4

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    #22
    Can you give me an idea of the budget then (I'm not aware of the pricing on the VTrak, as everything I've seen says "Contact for Pricing" :p)? ;)

    Must it be network based?

    Also, what type of array types do you really need (though what I'm thinking about supports 0/1/10/5/6/50/60)?

    Drive quantity (16 in the VTrak, but will it be full, and what kind of growth do you need)?

    Any information you can provide would help. :)
     
  23. UltraNEO* macrumors 601

    UltraNEO*

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    #23
    Currently using RAID 5, it's faster than RAID6 and offer more space, with my current configs there's just over 2.6Tb of work space (system and appz storage on other drives). Usually I have to shuffle/delete/create backups with every large project - multiple versions and stages of saving. It's becoming frustrating to the point I'd sooner have space available but I don't wanna break the bank. So I'm thinking about a suitable high speed solution, ideally offering 6~10Tb's (and the space to grow) for less than 10K. Possible?

    Those VTrak E-Class RAID ain't cheap, typically a 6TB unit with 8 drives comes in at a eye popping $11,223.00 USD (cheapest) or $211 a mth lease!! That's before adding it's fibre chancel interface and delivery!! On the Pro side, it does provide it's user space to expand at a later date since has the capacity of 16 drives but I assume as a lease unit, it's gonna be a little more hassle with paperwork.
     
  24. nanofrog macrumors G4

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    #24
    That's a massive jump from a CalDigit to the VTrak. You'd also want to note FC drives are anything but cheap. Essentially SAS drives, but cost even more. :(

    I was thinking go with a decent RAID card, and use good external enclosures.

    Say an ARC-1680ix24 (up to 28 drives without using SAS expanders), 3x 8bay enclosures, and the cabling. Beyond that, you'd need to use SAS expanders, but they can get you to 128 drives on this card. If you don't need that many ports, you could opt for the ARC-1680ix16.

    For an enclosure, this would be an example, though you may want a different format (rackmount example). Up to you. Redundant PSU's can be considered, and are standard on the rackmount I linked (12bay units, so only 2 needed for a 24 port card).

    From the internal ports to the enclosure, you'd need one these per port. Note, I linked the 1.0m cables on the assumption you'd use SATA drives (2.0m max, for active, which includes all cable lengths in the chain). You might be able to use the 2.0m versions, but it might be unstable (it would have to be tested with the gear you actually perchase). SAS can use longer cables, as it operates at a higher voltage.

    It's effectively the same as what you had with the CalDigit as far as how it hooks up, except you will have to have an open slot cover to route the cables off the internal ports.

    Hopefully this can give you some ideas, but would be cheaper than the VTrak by a substantial margin I think. ;) Let me know how you want to go. ;)
     
  25. UltraNEO* macrumors 601

    UltraNEO*

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    #25
    Well nano, just over a year ago prior to I signed this contract I thought 3~4Tb would be plenty lol.. and now look; I'm using more than I have and I'm struggling.

    So looking at your recommended ARC-1680ix24 and it's enormous potential and expandability options for a few grand seems very viable. Out of curiosity, what sort of performance gains would I'd achieve with the optional 2GB/4GB cache?
     

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