Date: Thu, 7 Sep 2000 10:33:13 +0930 From: Greg Lehey <grog@lemis.com> To: Mike Tancsa <mike@sentex.net> Cc: stable@FreeBSD.ORG Subject: Re: Vinum (was: RAID) Message-ID: <20000907103313.C7718@wantadilla.lemis.com> In-Reply-To: <4.2.2.20000906000615.03226880@mail.sentex.net>; from mike@sentex.net on Wed, Sep 06, 2000 at 12:29:06AM -0400 References: <00090310375700.05988@www.runapplications.com> <4.2.2.20000904120154.07455bd0@mail.sentex.net> <20000905101653.A49732@wantadilla.lemis.com> <4.2.2.20000904204407.033e2920@mail.sentex.net> <20000905115126.A14470@myhakas.matti.ee> <4.3.2.7.0.20000905090105.053a13f0@marble.sentex.ca> <20000905155032.A27690@futuresouth.com> <4.3.2.7.0.20000905165313.037652c0@marble.sentex.ca> <20000906084835.B21113@wantadilla.lemis.com> <4.2.2.20000906000615.03226880@mail.sentex.net>
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On Wednesday, 6 September 2000 at 0:29:06 -0400, Mike Tancsa wrote: > At 08:48 AM 9/6/2000 +0930, Greg Lehey wrote: >> Please make sure to use rawio in the tests. Other things, such as >> bonnie and dd, give better looking results, but they're not very >> related to what happens in practice. > I will certainly take a look at it. However, for now, I have been > using a number of bonnie processes simultaneously. The box I am > building is going to be just a pop3 server. So at any given time, a > number of popper processes running scanning through a users mailbox > to see how many messages they have seems to be well enough > approximated by a number of disk intensive processes like bonnie at > once. I'd really like to see the output of rawio, simply because it's more repeatable from one platform to another. > As for testing, so far so good. Actually, I was quite taken aback > by some of the results. It really does seem a lot faster, certainly > from the limited testing I have done. In one, test where I blast > email at the box as fast as I can from two outside hosts, it took > half the time deliver mail to 13,000 user mail boxes as compared to > the time it took on the 428 MegaRAID controller in a 3 disk striped > config with the same physical drives involved. You're saying Vinum is faster? > The other neat thing I have found so far, was that on a 256MB > machine, comparing the amr, mlx, da, ad to the vinum drive, the > vinum tests gave me the best even distribution of multiple processes > blasting on the disk. Running 15 bonnie -s 100 at once, all the > drivers except vinum tended to favor the first and second process in > terms of performance. vinum gave very uniform results across all the > processes which I guess if I saw 20 popper processes start up, all > accessing big mail boxes, I would want each to get equal disk > access! Hmm. I wonder if this is a coincidence. I don't think it's a plus for Vinum, anyway. I suspect that somewhere in the system we have a problem with process balancing. It's very obvious initializing Vinum subdisks, where the elapsed time for performing identical operations in parallel can vary by a factor of 2:1. > The only problem I have run into so far is creating a 3 disk RAID5 > array. Is this not possible ? Sure. > It *seems* to take the command OK (raid5 -v /dev/da0e /dev/da1e /dev/da2e), > but newfs gives > newmail# newfs -v /dev/vinum/vinum0 > newfs: /dev/vinum/vinum0: Input/output error > on a STABLE box from 2 days ago. Take a look at http://www.vinumvm.org/vinum/how-to-debug.html and send me the info I ask for there. > Am I better off in the end going with 4 drives in a RAID 10 config > instead ? That depends very much on what you want to do. RAID 10 will be faster, of course. Greg -- Finger grog@lemis.com for PGP public key See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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