Date: Fri, 29 Sep 2006 10:33:14 -0600 From: Scott Long <scottl@samsco.org> To: freebsd-stable@freebsd.org Subject: Re: Poor write performance with LSI 320-2 on 6.1-STABLE Message-ID: <451D4ACA.1040504@samsco.org> In-Reply-To: <20060928221505.GA75187@mail1.thewrittenword.com> References: <20060928221505.GA75187@mail1.thewrittenword.com>
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Albert Chin wrote: > I have an Intel S875PWP1 motherboard with a Pentium4 CPU@2.40GHz. PCI > bus is 33Mhz, 32-bit. I recently purchased an LSI 320-2/128MB on eBay > (though the card really looks like a PERC4/DS) and just ran some > bonnie++ tests on a RAID 1 array between two U320 drives for the first > channel and on a RAID 0 array between one U320 drive for the second > channel. The 320-2 has the latest LSI firmware, 1L47. > [...] > > I don't understand how #1 gives 16MB/s (RAID 1) while #3 gives only > 17MB/s. I'd expect #3 to be about x2 the performance of #1. > > The arrays are configured with "write-thru" write policy, "adaptive" > read policy, and "cachedio" cache policy. In LSI terms, "write-thru" means, "write cache is turned off". With that set, performance becomes very consistently describable as "poor", as your tests demonstrate. Linux can get around this a little bit in benchmarks by using larger I/O sizes than FreeBSD (FreeBSD is limited to 128K max, while Linux is not). These are very speedy cards once you put them into their intended configuration. With some decent SCSI disks and a PCI-X bus, it performs quite well. However, I'm actually kinda surprised that the card works at all in your 5V slot. Scott
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