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Advice on setting up RAID

Discussion in 'Hardware' started by JoKeR, 1 Dec 2004.

  1. JoKeR

    JoKeR What's a Dremel?

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    Hi, im on the verge of buying and installing a pair of 74gb raptors :D (just waiting for my new psu to become available over here mmmm X connect :naughty: ).
    I have a basic grasp of computer hardware but RAID is something completly new to me, can anybody give me some basic advice or point me in the direction of a good how to site.

    cheers :thumb:
     
  2. Mister_Tad

    Mister_Tad Will work for nuts Super Moderator

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    my advice on setting up raid (and presuming you are talking about raid0) is simple:
    dont

    there are no benefits to using raid0 in a desktop system
    and dont even *think* about setting up windows on a raid0 partition :duh:

    if you want some detailed info and testing, www.storagereview.com
     
  3. scoob8000

    scoob8000 Wheres my plasma cutter?

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    No offense Mister_tad, but I don't buy that. Can you provide any information to support that?

    I've been running windows off a raid0 setup for several years without any problems..

    Raid0 will stripe your data between two or more drives, so when your accessing a file your actaully reading and writing from two or more drives at once..

    The biggest downfall to raid 0 is if one drive dies, you lose all your data on both of them. If you do regular backups, this isn't a big problem.

    Especially with such a modern drive as the WD raptors. I'm trusting data to a stripe of two old 20gb drives, and I would be inclinded to trust it even more to two brand new raptors.

    One mistake not to make however is don't buy a cheap raid card. Also, don't even consider a software raid setup.

    A hardware raid controller does all the heavy work of striping your data, it's hardware dedicated to just that.

    A software raid (setup from inside windows using two ordinary drives on two ordinary ide ports) will make your processor do all the dirty work, and that type of raid I don't trust.

    Just my $ .02

    -scoob8000
     
  4. Mister_Tad

    Mister_Tad Will work for nuts Super Moderator

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    im not selling it, its fact
    theres heaps of info on this topic, have a gander at www.storagereview.com

    run it on a single drive for a performance boost
    the "speed increase" you are experiencing is purely psychosomatic

    im well aware of the principle behind it thanks.
    The case is that raid0 boosts the sustained transfer rates, you know what this helps? sod all. The only applications which benefit from boosted transfer rates are ones which deal with very large files, ie video editing, large format images, sound production. The downside of this is that the average access time is increased due to the nature of 2 heads seeking instead of a single one, which has a negative affect when dealing with small files, of which windows is full of, there is also the matter the overhead of the controller, which has a marginal impact on random access performance

    not particularly a big deal with new drives (but still something to think about when striping data), failure rates of decent drives are very low these days fortunately, and you should do backups regardless of raid or not (well f you want to get technical, raid0 is a misnomer as the acronym RAID implies redundancy, which is not given with raid0)


    food for thought
    http://www.storagereview.com/articles/200406/20040625TCQ_5.html

    http://faq.storagereview.com/SingleDriveVsRaid0
     
    Last edited: 1 Dec 2004
  5. scoob8000

    scoob8000 Wheres my plasma cutter?

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    Wasn't a stab at you, was just trying to explain it for JoKeR.


    I suppose I stand behind my benchmarks too much. I've never made any real world tests (windows boot times, game load times, average user things) myself.

    Also in the raid setup I have personal experiance with utilizes anciently slow hard drives. I'm sure a raid 0 setup of this nature will make a bigger differnce then more modern faster hard drives.

    -scoob8000
     
  6. Mister_Tad

    Mister_Tad Will work for nuts Super Moderator

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    if the sustained transfer rates of the drives in question are sufficiently low, then setting up a striped partition can have a positive impact, as the STR of a single drive may not be enough to feed applications, if that makes sense
    on any drive made within the last few years the data density is sufficiently high to provide STR more than high enough to remove this bottleneck on even low rpm drives.

    raid0 is nice for big numbers, but hard drive benchmarks tell you zero about real world performance. I have played with both scsi raid0 and ATA raid0, both returned very impressive transfer rates, neither performed up to par when comparing qualitative results to seperate drives.

    by all means still go for 2 raptors, but you would be better off using them seperately

    alternatively, taking the cost of 2 raptors and a decent sata raid card, a little bit more dosh can give you a nice new 15k scsi drive, a u160 scsi card and a large 7200rpm drive for storage
     
  7. webbyman

    webbyman Hax.

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    :hehe: Mister tad seems to know what hes talking about lol
     
  8. phuzz

    phuzz This is a title

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    of course, he might want to use RAID1 because he's paranoid about data loss....

    But to acctually answer Jokers question:

    Partly it depends on what hardware you're setting the RAID up on, I'm going to guess your motherboard has built in SATA RAID tho. First, connect your raptors up to a pair of SATA ports, depending on the motherboard, only some of them may be RAID'able, pick two that are. Usually that will mean two ports that are 'next to' each other, (eg, on my board I use the two ports connected to the Promise controller chip, not the built in ones which are in a different place on the board).
    Next turn on, and boot into BIOS, and make sure RAIDing is turned on, check your mobo manual, in fact, it'll probably take you through the whole process...
    (On MSI nForce 3 mobo's you also have to select which drives are avaliable to use in the RAID in the BIOS as well, and maybe on other mobo's as well)

    The next step will depend on the motherboard you're using, but usually, as you boot up you'll have to hit a key, or a combination (eg, CTRL+f on mine), to get into what's usually called 'Array Management' or somesuch.
    Here again it will depend on the hardware you're using, but you'll want to go for the option which sounds like 'create new array' or similar. Usually then you'll choose the hard drives you want to take part in the array (look for WD740GD in your case).
    Then it'll usually ask if you're sure you want to erase everything on the disks, funnily enough you don't answer no to this one ;)

    If you're installing windows on your new array, you might have to hit F6 during the first bit of the windows installer, and insert a floppy disk with drivers for your RAID. These should have come with your motherboard, if not, try the manufacturers website.

    If you're using an add in RAID card, hopefully it should come with decent instructions (ie better than this), and all the drivers and stuff, so that shouldn't be too much trouble.
    hope that helps
     
  9. JoKeR

    JoKeR What's a Dremel?

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    Thanks to all for your input guys, but the one thing i didnt mention the machine i will doing this for is a gaming machine. Building a second rig for the boring stuff.

    Like i said i'm completly new to RAID and I thought you had to run at least 2 HD's with RAID but as said above i could use just the one. If this is true would that be worth while, as i'm not that bothered about the loss of data.
    I know its sad but im one of the ever growing circle of people who want the most performance out of there rig.

    Again thxs for all your info :thumb:

    Btw my mobo is a IC7 and it is RAID compatable
     
  10. Mister_Tad

    Mister_Tad Will work for nuts Super Moderator

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    i think you deeply misunderstood something that was said above :eyebrow:

    raid stands for redundant array of independent/inexpensive disks
    "array" implies more than one, and more than one drive needs to be used for a raid array of any type (there are several different levels of raid, each meant for different purposes, and usually intended exclusively used in a multi-user environment)


    you can indeed just use a single drive in the pc, or 2 seperate drives, but that isnt raid

    edit: jimbo, pwned by 3 whole minutes, you fall asleep? :D
     
    Last edited: 1 Dec 2004
  11. jetsetjimbo

    jetsetjimbo Up-up and away

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    You can't set up raid using 1 drive. You need at least 2 drives in an array (set) with either Raid0, when the information is split (striped) accross the array or Raid1 the data is mirrored between the two drives for redundancy.

    With Raid1 this the total available storage will only be that of 1 drive (i.e. 74gb) but if either drive fails you can just replace it and the array will rebuild itself from the other drive.

    There are other types of raid array. This tutorial gives an overview of all the different types.



    Edit: Too slow :)
     
  12. Xen0phobiak

    Xen0phobiak SMEGHEADS!

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    he does ;)
     
  13. blknoel

    blknoel What's a Dremel?

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    he does know or he does seem? :hehe:

    On this I agree with Mister Tad, thats wat I was dreaming of 2x 36GB raptors, but then it turned out real world performance does not correspond to the optimistic numbers of Sustained Transfer Rate, game loading times were virtually unchanged, let alone a bit slower :D

    I'm interested in Windows boot time, particularly, dunno why :rock:

    and with 1 raptor, it got took 2 cycles of the running bar, for 2 in RAID0, it took 2 and a half for me :D ---> no gain :eyebrow:

    And he must have done much of reading before giving all that technical stuffs, and they make sense to me ---> for files of large blocks, a boost may be seen, but a $hitload of tiny files with tiny blocks (4k ->16k) like Windows may not benefit.

    EDIT: a small (and stupid perhaps) query guys, 15K SCSI, and 10K raptor, which one is...noisier :eyebrow:
     
  14. Mister_Tad

    Mister_Tad Will work for nuts Super Moderator

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    greatly depends on the scsi drive in question, but a new gen 15k drive will have a seek noise a bit louder than than a 74GB raptor, and the 36GB raptor is slightly noisier than the 74GB raptor, although the seagate 15k3 is about the same as a raptor (but not anywhere near the MAS or atlas15k in performance)

    the seek noise on 15k is quite a bit different as well, less of a chunky clicking than lower rpm drives and more of a vibrate/buzzing sort of noise

    the fujitsu MAS is also quite a bit different in noise characteristics than most other 15k drives, being a little lower pitched when seeking, due to the slightly larger platters than in all the other ones

    the idle spin on my 15k however, is completely inaudible, id presume its something to do with the frequency being over the hearing threshold :confused:
    can hear it spin up and spin down, but not idle, which is nice
     
    Last edited: 1 Dec 2004
  15. Jumeira_Johnny

    Jumeira_Johnny 16032 - High plains drifter

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    I too have been thinking about RAID. I have been looking at RAID1 for the boot drive, but using the Hitachi 80gig 7200rpm disks. I was wondering, in RAID1, do you see the same problem with the smaller windows files? or is data read/written differently then in RAID1? beyond the stripe and mirrior difference, I mean.
     
    Last edited: 2 Dec 2004
  16. Mister_Tad

    Mister_Tad Will work for nuts Super Moderator

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    there are no performance benefits or drawbacks with raid1 in practice (technically speaking performance is marginally lower but this is so slight that you would never know)
     

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