Date: Wed, 25 Jul 2007 19:02:58 -0600 From: Scott Long <scottl@samsco.org> To: Howard Goldstein <hg@queue.to> Cc: freebsd-stable@freebsd.org Subject: Re: [resolved, naively] Re: geom vs ich through ar device - benchmarks? Message-ID: <46A7F2C2.2090009@samsco.org> In-Reply-To: <46A7BF8C.5020909@queue.to> References: <46A4E8FA.6010403@queue.to> <46A7B3FB.7010504@queue.to> <46A7B7AF.6080308@samsco.org> <46A7BF8C.5020909@queue.to>
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Howard Goldstein wrote: > Scott Long wrote: >> Howard Goldstein wrote: >>> Testbed: Pair of WDC3200AAKS 320gb SATA, freshly newfsd 10gb filesystem >>> mounted with softupdates, remounted after each test >>> P4 @ 3ghz on a P4P800 in 6.2-STABLE, single user mode, ICH5R controller >>> detects these SATA-II drives inexplicably as SATA-I >>> >> ICH5 only support SATA-1. > Dang. Does anyone yield SATA-II speeds with the a PCI controller? I'm > not sure if 25-30MB/s is even possible with regular PCI > Even PCI-33 should be able to sustain about 100MB/s, enough to handle a single disk drive. Many controller are PCI-X or PCIe now, which has plenty of bandwidth for 4-8 drives. >>> Of course after this I used gmirror... >> Just so we're clear, the ICH5 doesn't have any firmware and doesn't >> >> actually do any RAID operations. What is has is hook into the system >> BIOS during boot. That hook allows the BIOS to do RAID-like operations >> during boot, until the OS takes over control of the devices. After >> that, it's up to the OS to do all the RAID work. The 'ar' driver is >> still software RAID, just like gmirror. What you've effectively done >> merely compare the performance of one software RAID stack to another. >> That's certainly an interesting comparison, but maybe not exactly what >> you had in mind. >> > It's helpful - thank you. Do you think I'm correct in assuming the > interface is pretty much saturated at this point and if I wanted > additional speed I'd need to start thinking bringing in additional or > faster interfaces? You should be able to sustain at least 70MB/s on a single modern drive with SATA-1 or SATA-2. If you're not getting that then something in the driver or the application is getting in the way. Even with the, um, "problems" that SiI controllers are famous for, you should be able to sustain a decent data rate on a single drive. Scott
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