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Thread: A new question...(I think)

  1. #1
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    Hi all

    Have the 2 drive G2 x15 raid and am very pleased with it. My question is this:

    I want a 3 drive array and a Cheetah boot drive. If I add a 3rd drive to the raid AND add a 4th drive to boot from (both of these on the second channel) Will having OS activity on the scsi bus interfere with video capture and the speed of the raid?

    Thanks
    Damien

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    Hi ya Damien,
    With your RAID physically attached to 1/2 (1 channel) of the PCI slot and the other drives physically attached to the other 1/2 I would think you would be giving each channel 32 bits of bandwidth evenly. Even at the max on that one channel you shouldn't be able to 'deplete' bandwidth from the other channel. Nor will you be anywhere near the designed max PCI bus throughput of 215mb/sec or so. (I was too listening to MacMikester )
    Rick

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    Hi Ricks

    That was along the lines of what I was thinking but I wanted to get a second opinion.

    Thanks for replying!

    Also I want to add another x15 to my raid but have been considering something a bit less bleeding edge (read:cheaper) for my boot drive. Currently I boot from the stock IBM 60gig and I definitely want to exceed its performance. Any thoughts?

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    Damien,
    Have you run ATTOs benchtest on your IBM 60gig. I get almost 40mb/sec on mine with it 1/2 full and all sorts of things running. That's not too bad. If you just want some cheap speed on the boot disk how bout trying a ATA hardware Raid on it? A RAID card and a second IBM 60 GXP will cost $350 or so and you'll double your speed. OSX compatable too.
    Rick

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    I do not have an OS X compatible ATTO bench util. I just bought the card though, is there a free upgrade path?

    When I was using OS 9 I ran "JouleRAID Benchmark" and the IBM was showing 38-39MB which I was happy with as far as that goes......but dangit I come from the old school of Macs and ATA just ain't right! It is supposed to be all scsi.....

    But seriously,

    I had briefly considered the hardware ATA raid and was pretty excited about it, but then I read here at the guru forums that someone was having stability trouble in a Quicksilver with the ATA raid but wasn't having the problem in a B&W which makes me think that the ATA Raid setup doesn't like the new PCI architecture. I have a 733 Digital Audio

    Another thing that concerns me about this is that a Striped array really isn't the place to be keeping your stuff.

    Is it true that a mirrored array will read with the speed of two drives? I know that they only write a single drive speed.

    I don't really want to boot from a striped array due to the higher risk of data loss. I'm hoping to keep the ATA drive for static storage, have a fast scsi boot drive and a super fast array for video

    I noticed that my two x15's spin up, do the initial read and are sitting idle BEFORE my IBM ATA drive even gets spun up


    Oh yeah, my ATTO card is 64 bit in my 733 64bit PCI slot.

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    Damien,
    I confess to being the one who wrote about the ATA RAID. I had installed in both the Quicksilver and the B&W. I had a couple early difficulties on both boxes. I did have a short but satisfactory experience with it in the Quicksilver, I left it in the B&W after the tests were done in it.

    Mike Breedan led me to believe with our latest discussion on the hardware RAID cards that they are quite dependable in the entire range of computers. I can say that since I solved a couple of other hardware issues on the B&W the ATA133 RAID has been flawless. I have it partitioned into equal OS9 and OS 10.1 volumes. Using the RAID for boot in both cases.

    Also had some brief exchange with rob-art at bare-feats, he also posted a writeup on the ATA133 RAID and mentions no reported reliability issues. I have yet to hear of any unsolved issues since I had my small setup problems, and I try to keep up with it.

    Another site that isn't mac related but that the technology issues all apply is Storage Review.com. The PC users have a large choice of ATA based hardware RAID card manufacturers. I'd bet that ATA RAIDs are more common in PCs than SCSI RAIDs. Again, not very many negative reviews are to be had.

    I am running a ATTO SCSI RAID on the Quicksilver and when it becomes reasonable I will totally switch the Quicksilver to OSX. Untill then the RAID is Running OS9 for the graphics programs and the ATA drives will have to do for OSX.

    I may add another ATA133 RAID card for the Quicksilver with the way it's worked in the B&W. I may decide that I want the literally double speed that the card gives and I already have the 2 IBM drives installed. I can't think of a cheaper accelerator for my QS.

    Rick
    Speed is its own reward.

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    Well this makes me feel a bit better but I am still leery of depending on a RAID for my static storage.

    If I know myself, the greed for speed will win and I will either get a Dual ATA to boot from and the Cheetah raid to brag about OR I will get a big Cheetah to boot from and the Cheetah raid to brag about.

    Does the ATA raid outperform a single g2 x15?

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    Ya gotta love it, if it wasn't for the addiction to more speed.......

    I'm still laughin. I don't know, what is the single X15 throughput?
    I suppose it comes down to which itch gets scratched.
    Rick

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    I have read that a minimum of 51MB a sec is to be expected by a single x15 but I have not heard what the avg throughput is

    This sounds like a job for .....SUPER-KAYE (or perhaps magician)

    The question is

    Will a hardware ATA RAID outperform a single G2 x15?

    Anyone.....anyone.....Bueller?

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    Well Damien, if a single X15 is in the 50s then the ATA RAID, at least with the IBM GXPs I used, will get in the mid 70s.

    I suppose that if one were to use the Western Digital Caviars that have the 8mb buffer that should go way up. I, unfortunatly don't have the bucks to go get a couple and find out just how fast they would be in a hardware raid0. Wish I had a bigger budget for funnin. Shoot, with a little money I'd be dangerous.

    I do know that having your Photoshop scratch disks on separate buses on different PCI slots can really have a great effect on progress bar lethargy, I have no idea what effect it would have on video. Couldn't hurt it though.

    I bet Kay'l have a few ideas that help though, he always cuts to the chase.

    Rick

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    Bueller here. When I first put together a 2x G2 X15 striped Raid back in early September here http://www.macgurus.com/ubb/Forum16/HTML/000044.html

    ATTO UL3D, various configurations of generation 2 X15s (ST318452LW):
    -------------------------------------------------------------------
    ATTO EPT, 8MB, no System Disk Cache, HFS+:
    PR-107.34, SR-058.86, PW-095.43, SW-060.58MB/s (One G2 X15 on UL3D firmware 1.50)
    PR-138.35, SR-112.64, PW-120.60, SW-115.45MB/s (Two G2 X15 on one channel, UL3D firmware 1.50)
    PR-205.50, SR-112.74, PW-123.94, SW-117.14MB/s (Two G2 X15 on two channels, one per channel, UL3D firmware 1.50)
    PR-135.84, SR-113.70, PW-132.85, SW-117.78MB/s (Two G2 X15 on two channels, one per channel, UL3D firmware 1.64)

    A couple of notes:
    1. The drives are faster now that they are broken in.
    2. UL3D Firmware 1.64 is faster.
    3. Those G2 X15s have Seagate firmware 0002. My latest are firmware 0004 which is slightly faster SW.

    However, I see no way that a single G2 X15 is going to match the mid 70's of an ATA hardware striped RAID.

    Damien, I missed your very first question, about striping three G2 X15s, two on one channel and one on the other channel. For reasons of symmetry, the Gurus do not endorse that. One other point that Louie and I discovered with legacy Macs and dual Miles2, with a symmetric striped RAID (2x, 4x, or 6x drives and a boot drive added), the RAID drives must be first on the physical chain and the boot drive last. Putting the boot drive first would cause errors with the RAID drives. Perhaps symmetry again. With the boot drive last on the chain, no problems. Now the UL3D may not have such problems with the boot drive first, also perhaps no problems with New World Macs, I don't know. I did try the UL3D running the very same striped RAID in a PTP but only with the boot drive last on one channel. That worked with no problems. k

  12. #12
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    Thanks Kaye

    I knew you were the one to ask!

    by going with a scsi boot I will be giving up roughly 10MB a sec as I see it. However I will also not be dependant on a Level 0 striped array for data integrity hmmmmm tough choice.

    If this

    IBM 60GB 7200 rpm ATA100 IDE Hard Drive (from the gurus)

    matches close enough to my stock Apple IBM 60 gig 7200 to allow the raid to happen (I have heard that the hardware raid card needs a very close match) then I could do it If I have to buy a matched pair of drives and the card it will be more than I want to spend on ATA

    I have about talked myself out of a hardware raid despite the slight speed increase

    If Apple ever allows Striped scsi booting I will be completely broke

    Will three x15's saturate a single bus on my ATTO UL3D?

    Is SoftRaid still on track for an early 2002 release of OS X Raid software and will it do Level 3 (which seems to suit my needs better than the others...highest thruput with acceptable data integrity/safety)

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    Will three X15s saturate a single channel on a UL3D? Actually I thought two X15s on one channel and two on the second channel were very near saturation until I ran a little test for Taffy.C here http://www.macgurus.com/ubb/Forum1/HTML/000211.html (about half way down the page). What I found is that three X15s on each channel was only slightly faster than two on each channel on the outer tracks, but on the inner tracks, two per channel fell off much more than three per channel. So my thinking now is that four per channel might offer slightly better performance on the outer tracks, and definitely better inner track performance.

    My guess is that if money is no object, 2x UL3Ds, 2x 4-bay Burlys which have dual channel capability, all the necessary internal Burly Granite LVD cabling and LVD terminators, and the necessary four external Granite cables, 8x G2 X15s, and a QuickSilver would be the ultimate, until something new out of all that mix comes along, like an ATTO UL4D or X20 or faster bus speed. k

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    Ok I think I have my plan now

    3 18.35gig x15's on a single channel Raid for video capture (preferably Raid 3 if Softraid supports it whenever Softraid gets here for X.1)

    1 60gig IBM ATA on the motherboard bus or external FW for slow static storage

    1 x15 36gig boot drive (& cable/term)

    Oh yeah and the Formac or Sony FW video cap device (Had to sell my FUSE card due to no OS X support)

    Unfortunately the quad channel 8 bay dual burlys and dual UL3D's are a bit out of my price range :-(

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    Out of my price range too though I have perhaps one half of the stuff needed. Maybe we can get Rick (Speed is its own reward) to do it. k

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    Will you take a third party check?
    Rick

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    Damien,

    When you get that 3 18.35gig x15's on a single channel Raid going, let us know how it tests out.

    Rick,

    I take all kinds of checks, but I don't think magician does. I'm on the left coast, he's on the right coast. k

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    I, too, could write the gurus a check for this stuff and it probably would make it there in only one bounce! 9 states away in only a single bounce, now THAT is some serious performance!





    [This message has been edited by Damien (edited 13 December 2001).]

  19. #19
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    No problem Kaye Will Do. But it will be February or March before I add to my array again. Got to get those Christmas bills paid off first

    I am on the middle coast Indiana is not quite landlocked we have about a foot and a half of "coast" on Lake Michigan

    [This message has been edited by Damien (edited 13 December 2001).]

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    I remember years ago trying to get into South Bend numerous times in a B737 in the winter during some of the worst lake effect snow storms I have ever seen anywhere. Plus the only runway was east-west, so there was a strong crosswind. k

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