Some systems may have 66 MHz PCI, or 64 bit. Or, just more than 1 PCI bus. My desktop system has 3 PCI buses, I think. Guy -----Original Message----- From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of Mark Hahn Sent: Monday, December 06, 2004 4:35 PM To: TJ Cc: linux-raid@xxxxxxxxxxxxxxx Subject: Re: Looking for the cause of poor I/O performance > > for comparison, a fairly crappy SiS 735-based k7 system with > > 64b-wide PC2100 can deliver maybe 1.2 GB/s dram bandwidth. > > hdparm -T is about 500 MB/s, and would probably have trouble > > breaking 200 MB/s with raid0 even if it had enough buses. > > > > an older server of mine is e7500-based, dual xeon/2.4's, with > > 2xPC1600 ram. it sustains about 1.6 GB/s on Stream, and about > > 500 MB/s hdparm -T, and can sustain 250 MB/s through it's 6-disk > > raid without any problem. > > hmmm.. In these cases, how does the throughput exceed the PCI bandwidth? Do > these boards have multiple busses? PCI-X? I didn't say they exceeded bus bandwidth ("if it had enough"). the latter does actually have multiple buses, some of which are pcix; that's pretty common among server boards. interestingly, even non-server desktop parts can exceed PCI bandwidth - I did a disk server a few years ago that used two chipset ATA ports and an add-in 4-port card to hit about 150 MB/s total (sustained). - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
