RAID 0 for desktops - Are there any pro's

I just decided to start this thread in response to multiple posters in seemingly every third (or so) thread on these storage forums.

Why would anybody recommend setting up a RAID 0 for a desktop computer (not a workstation) intended for office / gaming / internet browsing use? (99% of desktop users out there)

Now, before you RAID0 fanboys start responding rashly, please finish reading this post.

1) The most common argument given for RAID 0 is that "it is way faster." To quote one poster, "two 7200 RPM drives in RAID0 are faster than a single Raptor 150GB." I think the main question with that argument is, what "faster" really means. Sure, empirical tests indicate that you get faster transfer speeds. That's all fine and dandy, but several tests designed to compare RAID 0 performance to single drive performance indicate that this increase in transfer speed under ideal conditions translates into little or no improvement in the real life applications' (i.e. those things we really run on our desktop computers) performance.

2) Drawbacks: the most obvious one is that a fault of one drive renders the entire array faulty. The results of such a fault may vary drastically; if you had the array partitioned, you may lose that partition, or worst of all you may lose the entire array if the partition data gets lost. In response to many of the posters here, by mere consequence and a most elemental application of the probability theory, this makes
The Probability That RAID 0 array is degraded = N * Probability of A Single Drive Failing
Or simply if you are crazy (and wealthy) enough to set up a 4-drive RAID 0, it will be 4 times as likely to fail as one drive within that array (assuming they are all the same, which is the preferred scenario anyway).

Another drawback is portability. Most controllers, to the best of my knowledge and I may be mistaken here, use incompatible striping algorithms. And so, if your controller goes out, or for whatever reason you want to port your array to a different controller (i.e. new motherboard for built-in controllers or a better competitive add-on controller), you may not be able to just unplug the drives and plug them back in.

Here's a link that tends to suggest that it is improbable that “…RAID 0 offers increased performance for all or even most applications...”:
http://faq.storagereview.com/SingleDriveVsRaid0
With that said, can anyone present empirical tests that back up their claim that RAID 0 results in any significant performance benefit (for real life scenarios and not theoretical benchmarks) that outweigh the drawbacks of such a setup?

I think this should be a requirement for anyone recommending it to other people who come here for good information and advice.
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  1. We have 3 RAID 0 sets on the ASUS P4C800-E Deluxe
    with a Pentium 3.2 GHz Prescott CPU:

    (1) 2 x 74 GB SATA Raptor HDDs ~ 120 MB/sec.

    (2) 2 x 300 GB PATA Maxtor HDDs ~ 100 MB/sec.

    (3) 2 x 320 GB SATA Western Digital HDDs ~ 95 MB/sec.


    The speed at which the raw data passes under the
    read/write heads of one of these three HDDs is closer to
    60 MB/second.

    Unless a small file fits ENTIRELY within the IDE cache,
    the data rate will approximate 60 MB/second on these
    and similar HDDs. The latest 150 GB Raptor is seeing
    a raw data rate of ~ 70 MB/second.

    If a small file does fit ENTIRELY within the IDE cache,
    then the data rate will increase to the theoretical
    maximum of the interface speed: ATA/100, ATA/133,
    150 MB/sec. or 300 MB/sec.; otherwise NOT!

    The "133" in ATA/133 is the MAX for the old PCI bus,
    i.e. 133 MB/second.

    So, all of our tests indicate that a RAID 0 of 2 modern HDDs
    is faster than a single HDD, measuring the speed empirically.

    However, increasing the set to 3 or more HDDs on the
    old PCI bus should not improve the speed, because
    that bus has a maximum speed of 32 bits @ 33 MHz
    = 133 MB/second. Subtract about 10% for overhead, and
    that bus realistically is capable of only 120 MB/second MAX!

    Implementing a RAID 0 on the PCI-Express bus is much
    better, because it does not suffer from this low ceiling.

    For example, Users are reporting a LINEAR increase
    in data rates, by wiring more than 2 SATA-II HDDs
    to Intel's ICH7R I/O Controller Hub.

    For maximum speed, we would highly recommend
    either the latest 150 GB Raptor from Western Digital,
    or their excellent 400 GB model WD4000YR with
    Time Limited Error Recovery aka "RAID Edition",
    provided that the RAID 0 is wired to a modern
    PCI-Express bus.

    RAID 0 makes a lot of sense for the C: system
    partition, because program launch speeds increase,
    as will the speed of the Windows swap file and
    the browser cache. Other data-intensive applications
    should also speed up, e.g. COPERNIC DesktopSeach.

    A C: system partition should always be backed-up --
    preferably by writing a drive image file to a different
    HDD, or some other medium like an optical disk.

    The main problem that comes with C: on a RAID 0 set,
    is that image restores require the correct driver to be
    loaded, using the F6 sequence. All disk imaging
    software of which we are aware supports this feature,
    however.


    I hope this helps.


    Sincerely yours,
    /s/ Paul Andrew Mitchell
    Webmaster, Supreme Law Library
    http://www.supremelaw.org/
  2. Paul, very thorough and informative post, yet I still have a couple of questions:

    1) What do you use this set up for? It sounds like a server application, which is entirely different from the applications most users who are recommending (and get recommended) RAID 0 set-ups are interested in.
    2) I think that while your points regarding the potential benefits of a RAID 0 setup for the system partition make a ton of sense from the theoretical perspective, I am not so sure, based on several articles, that they would translate in the real-life benefit for most users [EDIT:] because RAID 0 benefits, as far as I understand, are only significant when sequential access is required [ENDEDIT].

    I think your hard-drive selection recommendations are most sound; yet again, probably better suited to the enterprise user.
  3. Quote:
    My point of having RAID-0 is having a faster drive than the fasted out there(being either SATA or SCSI).
    Even if it's 1% faster I want it!


    Exactly! All the little number add up I think. Say you get max 5-10% performance increase in certain instances with Raid 0. Then you get another 3% from the proc/FSB overclock. Then say another 4% from graphics card overclock. Mayber another 2-3% for that CAS2 memory. That's maybe around 20% for all of those! Flawed logic? Perhaps. Singular performance benefit with just RAID0? Probably not.

    Throw in a data drive to go along with that RAID 0 setup though and the biggest argument against the nth degree of failure is mitigated! All the games I have save to the other drive so you don't lose anything from that either. Throw in a system state backup and your office prefences & bookmarks and you lose nothing! Well, except maybe time to reinstall.
  4. Why? Because I can and it is f'n fffaaassst!
    This is my 3rd RAID0 array in 4 years.
    The first one ran for 3 yrs till I upgraded the PC, but array did not fail.
    Second was for several months, but I needed the second drive for another machine.
    Third, on Opteron 175 build now, with 2x74gig Raptors!!!
  5. Quote:
    For me it was to get the lowest access time+fastest I/O+lowest $ for my game server.

    2x18GB Cheetah X15 was my solution. 8) (The SCSI RAID card costed me two arms tho)


    Jeeze man, you must be hung like Chuck Norris then to play your games....
  6. Or an Oompa Loompa... [/shrug]
  7. You say that a RAID 0 system drive needs to be backed up, however I have yet to find backup software that can restore to a RAID 0 array on either of my motherboard controller.

    When I boot to true image 8 for example Raid 0 drives show up as unformatted and RAID 1 drives show up as two drives with identical content.

    Is this a common problem with "software" raid controllers, or am have I just been unlucky.
  8. Yes it is problematic to Ghost RAID 0 systems. I have been unable to successfully make a Ghost of my 2x74GB Raptors in RAID 0. To fix the problem, I have threw in a 80GB WD as a backup drive. Any data that is critical on the RAID gets backed up to my 80GB drive. Although this isn't an actual clone, and if one of my Raptors would go, I would have to reformat, at least my important data is not lost. People build RAID 0 for SPEED, and RAID 1 for redundancy. I opted for speed, and RAID 0 owns sequential files such as 20GB files for video editing.

    My System:
    http://amdgamingrig.dyndns.org
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