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проблема с nfs при использовании udp-транспорта - mb
проблема с nfs при использовании udp-транспорта
Появилась при использовании udp-транспорта для nfs, после изменения транспорта на tcp проблема исчезла.

Инфа по теме:

Ветка в архиве рассылок freebsd-stable.

Сообщение в этой ветке:
Excerpt from the mount_nfs(8) manpage:
"Due to the way that Sun RPC is implemented on top of UDP (unreliable datagram) transport, tuning such mounts is really a black art that can only be expected to have limited success."

Ещё одно сообщение:
A server attached with 1Gb ethernet and clients with 100Mb connections. Server begins sending data to a client. The client pipe is narrower and the switch begins to buffer the frames. Switches _do not_ have very much buffer space. A high-end switch may have 2MB. Likely some of this can be shared between ports; some will be reserved per port. Let us assume all of the memory is on.
d(Memory_Used)/dt = 1000Mb/s - 100Mb/s = 900MB/s.
Thus... in less than 10ms the switch will run out of buffer space... and then *drop* frames.
oops. bye-bye UDP NFS.

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