Date: Mon, 06 Mar 2006 10:00:26 +0700 From: Beastie <beastie@mra.co.id> To: Nikolas Britton <nikolas.britton@gmail.com> Cc: Liste FreeBSD <freebsd-questions@freebsd.org>, Alex Zbyslaw <xfb52@dial.pipex.com> Subject: Re: SATA Raid (stress test..) Message-ID: <440BA5CA.2070202@mra.co.id> In-Reply-To: <ef10de9a0603030951p15ea49fei1d6d8fc56350feb9@mail.gmail.com> References: <61560.207.70.139.52.1139628926.squirrel@www.compedgeracing.com> <44052663.7000802@mra.co.id> <440565FF.3030002@mra.co.id> <44058D9E.3010801@dial.pipex.com> <440675E0.1020204@mra.co.id> <4406CB4D.5050300@dial.pipex.com> <ef10de9a0603020641t7014bf4cn9c9cc08b8d62af29@mail.gmail.com> <44072515.6080105@dial.pipex.com> <ef10de9a0603021550t54024c8bra7bf5905409f36fa@mail.gmail.com> <44082439.6070101@dial.pipex.com> <ef10de9a0603030951p15ea49fei1d6d8fc56350feb9@mail.gmail.com>
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This is a multi-part message in MIME format. --------------010501080304090606070006 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Nikolas Britton wrote: >On 3/3/06, Alex Zbyslaw <xfb52@dial.pipex.com> wrote: > > >>Nikolas Britton wrote: >> >> >> >>>>Please can you be careful when you attribute your comments. You've sent >>>>this email "to" me, and left only my name in the attributions as if I >>>>were someone suggesting either dd or diskinfo as accurate benchmarks, >>>>when in fact my contribution was to suggest unixbench and sandra-lite. >>>>Maybe you hate those too, in which case you can quote what I said >>>>in-context and rubbish that at your pleasure. >>>> >>>> >>>> >>>> >>>Yes I see your point, it does look like I'm replying to something you >>>wrote. This was a oversight and I am sorry. >>> >>> >>> >>> >>OK. >> >> >> >>>Remember that 105MB/s number I quoted above?, that's just the >>>sustained read transfer rate for a big ass file, I don't need to work >>>with big ass files. I need to work with 15MB files (+/- 5MB). After >>>buying the right disks, controller, mainboard etc. and lots of tuning >>>with the help of iozone I get: 200 - 350MB/s overall (read, write, >>>etc.) for files less then or equal to 64MB*. >>> >>>So anyways, that's what iozone can do for you. google it and you'll >>>find out more stuff about it. >>> >>> >>> >>> >>Thanks for the info. I think I can only dream about numbers like like >>yours. Iozone looks to be in the ports so I see some of my weekend >>disappearing looking at it :-) >> >> >> > >It runs on over two dozen operating systems, including windows. Their >are two primary reasons I can get such high transfer rates from simple >SATA drives. The first one was the selection of the mainboard that had >a PCI-X slots, I built this system before PCI-Express mainboards and >controllers hit the market. The PCI bus is severely restricted and >obsolete, I'm simply going to post the theoretical maximum throughput >in MB/s for the various bus standards: > >f(x,y) = x-bits * y-MHz / 8 = maximum theoretical throughput in MB/s > >PCI: 32 bits * 33 Mhz / 8 = 132 MB/s (standard PCI bus found on every pc) >PCI: (32bits, 66MHz) = 264MB/s (Cards are commonplace, mainboards aren't) >PCI-X: (64, 33) = 264MB/s (obsolete, won't find it on new boards.) >PCI-X: (64, 66) = 528MB/s (Commonplace.) >PCI-X: (64, 100) = 800 >PCI-X: (64, 133) = 1064 (Commonplace.) >PCI-X: (64, 266) = 2128 >PCI-X: (64, 533) = 4264 (very hard to find, even on high-end equipment.) > >PCI-X version 1 (66MHz - 133MHz) and PCI-X version 2 (266MHz - >533MHz). PCI-X is backwards compatible with PCI and slower versions of >PCI-X, for example you can put a standard PCI card in a PCI-X 533MHz >slot and it will simply run at (32, 33) similarly a 66 MHz PCI card >will run at (32, 66) and so on and so forth. PCI-X is also forwards >compatible in the fact that you can run a 133MHz PCI-X card in a >standard (32, 33) PCI slot. Because of the backwards and an forwards >compatibly I feel that PCI-X is superior to PCI-Express, *BUT* >PCI-Express moving forwards is far far superior to PCI & PCI-X because >it does not have 13 years of legacy to remain compatible with, it's >cheaper to produce, and it's already in lower-end desktop systems as a >replacement for AGP thanks to all the gamers. A few years from now PCI >will end up where ISA / EISA are. I'm veering way off topic so I will >not go into anymore details about PCI, PCI-X, and PCI-Express. Google >around for the shortcomings of PCI / PCI-X and why PCI-Express is the >future. > >PCI-Express: PCIe is not compatible with PCI or PCI-X (except for PCIe >to PCI bridging) and it's just, well, totally different from the PCI >spec and I'm already way off topic so again just google the details. >It's theoretical maximums are expressed in Gigabits per second but I >will convert them to MB/s for comparison with PCI and PCI-X. > >x1: 2.5Gbps = 312.5MB/s >x2: 625MB/s >x4: 1250MB/s >x8: 2500MB/s >x12: 3750MB/s >x16: 5000MB/s >x32: 10000MB/s > >Anyways back on topic, what was the topic? Oh yes, why you won't see >200MB/s - 350MB/s if your using a standard PCI slot. If you look back >up all the way at the top you will see that the standard PCI bus is a >crap shoot and that it's limited to a theoretical maximum of 132 MB/s. >What this means is that your RAID controller and the disks attached to >it and the cache buffers attached to the disks are all capped at that >theoretical maximum of 132MB/s. Then you have to take into account >that the PCI bus is shared with other devices such as the network >card, video card, USB, etc. Your RAID controller has to fight will all >these devices and a 1Gbit NIC card can eat up 125MB/s (12.5MB/s for a >100Mbit NIC). > >The next reason for those high gains is because I picked drives with >16MB cache buffers and that I'm insane enough to run a production >server with the write-back cache policy enabled on the array >controller and enabling the write cache on the disks. This is stupidly >insane unless you've planned for the worsts. The worst case scenario >would be that you corrupt the array into an unrepairable state and >loose everything if you had a power failure. > > > >-- >BSD Podcasts @ http://bsdtalk.blogspot.com/ >_______________________________________________ >freebsd-questions@freebsd.org mailing list >http://lists.freebsd.org/mailman/listinfo/freebsd-questions >To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org" > > > attach iozone result of amrd0 with 4 spindle Seagate Baracuda 300 Gb SATA II (1 hotspare) w/ Intel SRCS16 PCI-X Is that fast or what ? :) regards reza --------------010501080304090606070006--
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