Userslly it is considered best practice to use nics from a known comparable vendor for example Intel dual port nics can be found on sites like Amazon or neerhg for a reasonable amount of $.
On November 18, 2022 8:02:43 PM EST, David Christensen <dpchr...@holgerdanske.com> wrote: >On 11/18/22 05:23, hw wrote: >> On Tue, 2022-11-15 at 16:42 -0800, David Christensen wrote: >>> On 11/15/22 07:15, hw wrote: >>>> On Tue, 2022-11-15 at 12:38 +0100, hw wrote: >>>>> On Mon, 2022-11-14 at 13:21 +0100, hw wrote: > >>>>> Any ideas? Backups over an 1GB link are excruciatingly slow ... >>>>> >>>> >>>> Update: I booted a Fedora live system and the connection is also >>>> intermittent. >>>> So it's not a Debian issue. It's still an issue, though ... >>> >>> >>> What is the cable type? Length? Factory or home made? >> >> I got a new cable today which is rated as cat 8.1. It's only 1.5 meters >> long. >> I have tried 3 different cables now, two of them about 1.5 and another 10 >> meters >> long. Before I got the new cable, I tried the other port on the nic, and it >> made no difference. >> >> Even with the new cable, the connection is intermittent :( > > >Different category cables have different characteristic impedance, and the >NIC's are designed for specific cables. The EE buzzword is "transmission >line". You want to use the cables that Intel designed for -- Category 6A or >Category 6, 100 meters or 55 meters maximum (respectively): > >https://www.intel.com/content/www/us/en/support/articles/000007404/ethernet-products.html > > >I do not see a specification for minimum length; either on Intel or STFW. >Back in the day of 10BASE-*, I seem to recall hearing, reading, and/or >learning 2 meters minimum. > > >So, I suggest trying a Category 6A factory patch cable at least 2 meters long. > > >>> What is connected to the other end of the cable? If it is a NIC in >>> another server, what happens if you swap the two NIC's? >> >> It's connected to a Broadcom NetXtreme II BCM57810 in another server. The >> other >> server has an identical mainboard and CPU in it, and the other port on the >> Broadcom is connected to a client with the same card, and that connection >> works >> fine. So I'm assuming that the Broadcom card is ok. > > >What OS's for the various machines? > > >Do you compile your own kernels and/or NIC drivers? > > >> I'm about to move the client into a new case in a couple days and then I >> might >> swap the Broadcom from the client into the backup server. > > >If you have another Broadcom NIC, what happens if you swap it with the Intel >NIC in the backup server? > > >> Maybe I can reseat the heat sink on the card with new thermal paste. >> Overheating might explain why the connection is intermittent. > > >Do you have any diagnostic information that indicates the Intel NIC is >overheating? > > >David >
