RAID question #2

Discussion in 'OT Technology' started by deusexaethera, May 16, 2006.

  1. deusexaethera

    deusexaethera OT Supporter

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  2. rsxm5

    rsxm5 OT Supporter

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    I don't have experience with that card in particular, but from experience, PNY products seem to be decent and they have good tech support if something does go wrong. That is a decent price for those features as well... looks good in my opinion.
     
  3. deusexaethera

    deusexaethera OT Supporter

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    Yeah. It only does RAID-3, not RAID-5, but that's not too big of a deal. I don't have a swapfile on my machine, so the amount of data that I'd be writing to the array (RAID-3 suffers in write speed but has great read speed) would be minimal.

    Now I just have to choke down the price of 3x 74GB Raptors. Why not the 150GB ones? Because they're completely out of my price range. Besides, I do fine with a 60GB drive now, so 137GB will be quite pleasant for a good long time.
     
  4. P07r0457

    P07r0457 New Member

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    So you're telling me that you'd actually SAVE money by getting two 250GB drives, but you're just wanting the complexity of RAID?

    sounds stupid.
     
  5. keleko

    keleko yes, he is

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    drive mirroring ftw
     
  6. rsxm5

    rsxm5 OT Supporter

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    Are you using this for storage or performance?
     
  7. deusexaethera

    deusexaethera OT Supporter

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    Mostly for performance. As I said before, I have a single 60GB drive now, and while it's 3/4 full it's taken me a long time to fill it, so massive storage capacity isn't a concern. Most of that storage is for games, which I just uninstall when I haven't played them for a long time. At the same time, over the course of the time I've had my computer the HDD has really become the bottleneck, not least because it still runs on PATA-100.

    To address Jolly's point that I could save money buying two drives and mirroring them:

    With a mirrored setup, each of the HDD ports has to provide the full bandwidth needed to transfer a block of data. With a RAID setup, each of the HDD ports only has to provide the inverse fraction of the full bandwidth needed. Even with the 50% parity overhead on a 3-disk RAID, that still translates to a 50% reduction in used bandwidth per HDD port, or a 100% increase in the amount of total available bandwidth across the entire RAID, as compared to a simple 2-disk mirror.

    - - -

    Raptors have 4.7 milliseconds faster seek-and-read time than Barracuda's do (I would get Barracudas any day if they had the same access time), and that translates to 10.2 million clock cycles per-disk-access that my CPU would be using to do work instead of sitting around, waiting, and lagging up my system. I could buy two 150GB Raptors, but I don't have any onboard SATA ports or a hardware RAID and I don't want to waste the CPU power and memory running a software mirror (which still involves confirming that the mirror is accurate and can end up using XOR operations to do so), so I'll still need to buy a RAID card to run the setup.

    2x 150GB Raptors + PNY RAID card = $640 from NewEgg.com
    3x 74GB Raptors + PNY RAID card = $570 from NewEgg.com

    - - -

    50% overhead for a 3-disk RAID is less than 100% overhead for a 2-disk mirror, and that means if a single disk fails and can't be re-initialized, I'll be throwing away less of my initial investment in the new HDD setup.

    - - -

    All rational explanations aside (see above), RAID is sexy and I want one. Custom tuning isn't always about the bang-to-buck ratio, even though it does seem to be on my side in this scenario. Or...do those neon exhaust fans and hydraulic access doors really make computers run better?

    I, for one, decided to be practical and install air filters instead. My computer is dust-free for five years. (most of the parts are different now, though)
     
  8. EvilSS

    EvilSS New Member

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    Ah, it's one of those funky NetCell cards. These don't work like run of the mill RAID cards. Google NetCell to find out how it actually works. That's the reason it only supports RAID 3.

    From the reviews I've seen of them they do OK performance wise.
     
  9. deusexaethera

    deusexaethera OT Supporter

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  10. EvilSS

    EvilSS New Member

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    It's an interesting device. Definitely consumer oriented (which is a good thing if you are a consumer).

    Do be aware that the CPU article you posted is almost entirely a marketing piece for the NetCell. Google around for some more technical reviews and benchmarks. It does get pretty good reviews. Nothing spectacular, but nothing damning either.
     
  11. deusexaethera

    deusexaethera OT Supporter

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    Yeah, I know it's a puff piece. It's way too sweet to be written by an antisocial computer type like myself (and most of the people I know). I also know that the very nature of RAID-3 lends itself to bottlenecking on massive disk-write operations, though it makes up for that during massive disk-read operations by not having to burden every HDD port with parity data that is useless 99% of the time. It's still nice to get an explanation of what NetCell does, though. And let's face it, stellar RAID cards have no business being in home PCs anyway. If I get better than 1.4MB/s random-read-and-rewrite speed, and better than 29MB/s sequential-read speed, then it will be an improvement over my current setup.
     

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