In 2.6.10 there has been a "bug" introduced. You may also call it a feature, but its a crappy
feature for big servers. It seems the kernel is dynamically adjusting the buffer-space available for
sockets. Even if send-buffer has been set to 1024 KB, the kernel blocks at less if there are enough
sockets in use. If you have 10 sockets with 1024 KB each, they do not block at all, using full 1024
KB. If you have 4000 sockets, they only use 200 KB. So it seems its blocking at 800 MB. This is
good, if you have a 1/3 system, because else the kernel would run out of low mem. But I have a 2/2
system and I need them for buffers. So what can I do? Where can I adjust the "pool"?
Christian Schmid - RapidTec