On Thu, 12 Dec 2002, Leigh Wanstead wrote: > Take a look at > http://www.syskonnect.com/syskonnect/performance/gig-over-copper.htm. I was > really excited about gigabit before, as vendor promise 10 times than fast > ethernet. Now I realized that cheaper gigabit NIC only give me 3 time's > performance than normal fast ethernet. So I would rather use channel bonding > to combine two fast ethernet cards which is really good performance and save > money. Yes and no. If you only run 32bit 33MHz PCI and you're going to use a file server, you run into the 133 megabyte/s PCI limitation really quickly giving you only the 250-300 megabit or so you specify above. My record so far on a single TCP session over GigE is 530 megabit/s with a 32bit/33MHz bus but this was just a performance tester, no disk I/O involved. This was with a Syskonnect 9822. If you want higher speeds you have to go into 64bit/66MHZ, tweak TCP settings and buffers, have serious RAID controllers preferrably with SCSI drives, preferrably choose another platform than Intel, etc. It's the interrupt load of the intel that kills, so if you want high speeds locally you go for higher MTU which brings up performance really quickly. If you only need "slightly more than 100 meg" then as you say, two or three FE cards is really economical, especially in the switch end as GigE switch ports are still quite expensive (even as prices are dropping, cheapest GigE switch I have found so far is the Dell Powerconnect 5012 at $100/port). -- Mikael Abrahamsson email: swmike@swm.pp.se - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
