Re: Network speed degredation?
Believe it or not, disk I/O bandwidth is often the culprit in situations like this. Try moving the same amount of data from disk to disk and see what happens. Make sure you invalidate the cache if you do this in a loop to overcome the effects of extensive read caching. I think you'll find that your disks can't keep up with gigabit speed connections. -Alex P.S. You can run iostat to get an idea of how much data/how fast you can actually write to drives. - Original Message - From: "Ken D'Ambrosio" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, April 01, 2003 4:51 PM Subject: Network speed degredation? Howdy, all. I've got something that might be worth of April Fool's if it weren't for the facts that a) it's been happening for a while, and b) it's really annoying. Specifically, my NICs, in at least two of my machines, are going at roughly 1/10th the speed they're spec'd for. I fully understand that a 100Mbit NIC will never actually see 100 Mbit -- more like 80. And for a Gbit NIC, 600 Mbit would be closer. But right now, for example, my Gigabit NIC is pushing data at 5.6MB/s -- or roughly 45 Mbit/s. I just switched from the 100 Mbit EEPro100 'cause it was going at 8 Mbit/s. According to dmesg, they're recognized as they should be, and the switch shows them as having autodetected at the appropriate rate as well. (Note, also, that everything's running at full duplex.) One last data point: it seems to go reasonably fast -- at least three times faster than it does later -- during the first couple hundred megabytes. I'm assuming that that's cached stuff. However, the hard drives (I've checked the specs) should all be able to come close to, or even exceed, gigabit transfer rates, and the machines aren't busy doing anything else, so I don't think that drive access should be the bottleneck. Oh: 2.4.20, Debian. Any hints/suggestions/etc., would be greatly appreciated. Thanks, -Ken ___ gnhlug-discuss mailing list [EMAIL PROTECTED] http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss ___ gnhlug-discuss mailing list [EMAIL PROTECTED] http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss
Re: Network speed degredation?
Check out mii-tool - it might help. You can use it to query the current MII settings and to nail them where they should be if they aren't right. Sometimes two NICs fail to properly negotiate their optimal settings and (say) a 100Mb-FD connection might end up running at (say) 10Mb-HD. Worth a try... ___ gnhlug-discuss mailing list [EMAIL PROTECTED] http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss
Re: Network speed degredation?
On Tue, 1 Apr 2003, Ken D'Ambrosio wrote: > Any hints/suggestions/etc., would be greatly appreciated. Have you tried forcing the switch and network cards to 100/Full? Auto Detection often has issues. Ben -- Make happy those who are near, and those who are far will come. ___ gnhlug-discuss mailing list [EMAIL PROTECTED] http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss
Network speed degredation?
Howdy, all. I've got something that might be worth of April Fool's if it weren't for the facts that a) it's been happening for a while, and b) it's really annoying. Specifically, my NICs, in at least two of my machines, are going at roughly 1/10th the speed they're spec'd for. I fully understand that a 100Mbit NIC will never actually see 100 Mbit -- more like 80. And for a Gbit NIC, 600 Mbit would be closer. But right now, for example, my Gigabit NIC is pushing data at 5.6MB/s -- or roughly 45 Mbit/s. I just switched from the 100 Mbit EEPro100 'cause it was going at 8 Mbit/s. According to dmesg, they're recognized as they should be, and the switch shows them as having autodetected at the appropriate rate as well. (Note, also, that everything's running at full duplex.) One last data point: it seems to go reasonably fast -- at least three times faster than it does later -- during the first couple hundred megabytes. I'm assuming that that's cached stuff. However, the hard drives (I've checked the specs) should all be able to come close to, or even exceed, gigabit transfer rates, and the machines aren't busy doing anything else, so I don't think that drive access should be the bottleneck. Oh: 2.4.20, Debian. Any hints/suggestions/etc., would be greatly appreciated. Thanks, -Ken ___ gnhlug-discuss mailing list [EMAIL PROTECTED] http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss