Thanks for this information, RTT is around 1ms-2ms , so i near the theorical throughput,
Regards, Nicolas Prochazka. 2014-02-20 19:20 GMT+01:00 Andrew Deason <[email protected]>: > On Thu, 20 Feb 2014 14:33:15 +0100 > nicolas prochazka <[email protected]> wrote: > >> I do some benchmark , >> cat /afs/mycell.com/bigfile > /dev/null on openafs clients >> and i see a bottleneck of 25MBytes/s on server side ( fileserver process) . >> My ethernet link are 1Gbit/s >> >> How can I suppress this bottleneck ? > > Do you know what the RTT is between the server? (just 'ping' the server > for an approximation) > > The maximum theoretical throughput you'll get from openafs right now is > somewhere around ((32 * 1400) / RTT) bytes per second (due to some > limitations in the transport mechanism). That means if your RTT is on > the order of 10ms, the maximum throughput you'll see is is 4 or 5 MiB/s. > If your RTT is around 1ms, you'll see a maximum of around 40 or 50 > MiB/s. That is the theoretical max, so the actual throughput you'll see > will be less. > > There are other potential bottlenecks, of course, but that is often the > biggest factor when someone is surprised at the low transfer rates that > they see. There are some efforts underway to alleviate those > restrictions, but you can't do much about it just by "tuning" clients or > servers etc. > > -- > Andrew Deason > [email protected] > > _______________________________________________ > OpenAFS-info mailing list > [email protected] > https://lists.openafs.org/mailman/listinfo/openafs-info _______________________________________________ OpenAFS-info mailing list [email protected] https://lists.openafs.org/mailman/listinfo/openafs-info
