> 2012-10-30 19:21, Sebastian Gabler wrote: > > Whereas that's relative: performance is still at a quite miserable > > 62 > > MB/s through a gigabit link. Apparently, my environment has room for > > improvement. > > Does your gigabit ethernet use Jumbo Frames (like 9000 or up to 16KB, > depending on your NICs, switches and other networking gear) for > unrouted (L2) storage links? It is said that traditional MTU=1500 > has too many overheads with packet size and preamble delays between > packets that effectively limit a gigabit to 700-800Mbps...
Erm… That's not true. IPv4 header is 20 bytes. TCP header the same, meaning 40 bytes in total out of 1500 bytes "payload", leaving 1460 bytes left for real payload, or 97.3%. An overhead of 20-30% is *not* correct. The ~3% overhead matches well what I see in practice on my networks. You will get a gain with jumboframes, but mostly lower CPU use for handling the packets, and especially in iSCSI environments, but not much for the lower packet size overhead… Vennlige hilsener / Best regards roy -- Roy Sigurd Karlsbakk (+47) 98013356 [email protected] http://blogg.karlsbakk.net/ GPG Public key: http://karlsbakk.net/roysigurdkarlsbakk.pubkey.txt -- I all pedagogikk er det essensielt at pensum presenteres intelligibelt. Det er et elementært imperativ for alle pedagoger å unngå eksessiv anvendelse av idiomer med xenotyp etymologi. I de fleste tilfeller eksisterer adekvate og relevante synonymer på norsk. _______________________________________________ OpenIndiana-discuss mailing list [email protected] http://openindiana.org/mailman/listinfo/openindiana-discuss
