Dan Naumov wrote: > On Mon, Jan 25, 2010 at 2:14 AM, Dan Naumov <dan.nau...@gmail.com> wrote: >> On Sun, Jan 24, 2010 at 11:53 PM, Alexander Motin <m...@freebsd.org> wrote: >>> Dan Naumov wrote: >>>> This works out to 1GB in 36,2 seconds / 28,2mb/s in the first test and >>>> 4GB in 143.8 seconds / 28,4mb/s and somewhat consistent with the >>>> bonnie results. It also sadly seems to confirm the very slow speed :( >>>> The disks are attached to a 4-port Sil3124 controller and again, my >>>> Windows benchmarks showing 65mb/s+ were done on exact same machine, >>>> with same disks attached to the same controller. Only difference was >>>> that in Windows the disks weren't in a mirror configuration but were >>>> tested individually. I do understand that a mirror setup offers >>>> roughly the same write speed as individual disk, while the read speed >>>> usually varies from "equal to individual disk speed" to "nearly the >>>> throughput of both disks combined" depending on the implementation, >>>> but there is no obvious reason I am seeing why my setup offers both >>>> read and write speeds roughly 1/3 to 1/2 of what the individual disks >>>> are capable of. Dmesg shows: >>>> >>>> atapci0: <SiI 3124 SATA300 controller> port 0x1000-0x100f mem >>>> 0x90108000-0x9010807f,0x90100000-0x90107fff irq 21 at device 0.0 on >>>> pci4 >>>> ad8: 1907729MB <WDC WD20EADS-32R6B0 01.00A01> at ata4-master SATA300 >>>> ad10: 1907729MB <WDC WD20EADS-00R6B0 01.00A01> at ata5-master SATA300 >>> 8.0-RELEASE, and especially 8-STABLE provide alternative, much more >>> functional driver for this controller, named siis(4). If your SiI3124 >>> card installed into proper bus (PCI-X or PCIe x4/x8), it can be really >>> fast (up to 1GB/s was measured). >>> >>> -- >>> Alexander Motin >> Sadly, it seems that utilizing the new siis driver doesn't do much good: >> >> Before utilizing siis: >> >> iozone -s 4096M -r 512 -i0 -i1 >> random >> random bkwd record stride >> KB reclen write rewrite read reread read >> write read rewrite read fwrite frewrite fread freread >> 4194304 512 28796 28766 51610 50695 >> >> After enabling siis in loader.conf (and ensuring the disks show up as ada): >> >> iozone -s 4096M -r 512 -i0 -i1 >> >> random >> random bkwd record stride >> KB reclen write rewrite read reread read >> write read rewrite read fwrite frewrite fread freread >> 4194304 512 28781 28897 47214 50540 > > Just to add to the numbers above, exact same benchmark, on 1 disk > (detached 2nd disk from the mirror) while using the siis driver: > > random > random bkwd record stride > KB reclen write rewrite read reread read > write read rewrite read fwrite frewrite fread freread > 4194304 512 57760 56371 68867 74047
If both parts of mirror uses same controller, it doubles it's bus traffic. That may reduce bandwidth twice. The main benefit of siis(4) is a command queuing. You should receive more benefits on multithread random I/O. -- Alexander Motin _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
