selecttest tool

[JINMEI Tatuya / 神明達哉]

At Thu, 31 Jul 2008 10:43:21 -0500,
Walter Gould <gouldwp at auburn.edu> wrote:

> Here are the results from one of our linux servers:
> 
> # ./selecttest
> selecttest: nsocks = 4093, TEST_FDSETSIZE = -1, FD_SETSIZE = 1024, 
> sizeof fd_set = 128
> created 4093 sockets, maxfd = 4095
> FD_CLR test...OK
> FD_SET test...OK
> select test...OK
> 
> Based on the above, why do I get the "too many open file descriptors" 
> error when I run 9.5.0-P1? Help my simple mind understand this. :) Does 

There are several reasons.  One big issue is BIND9 internally limited
the possible number of open files to FD_SETSIZE.

> this mean that P2 will run as expected on this machine or will it give 
> "too many open file descriptors" error also?

The former (but you'll have to build BIND with a reasonable large
value of ISC_SOCKET_FDSETSIZE).  Note, however, this doesn't mean P2
will solve all problems that P1 had.  For example, if P1 made named
busy (wrt CPU load), it's pretty likely that P2 will also make it
busy.  So, you'll have to carefully watch the server behavior.

---
JINMEI, Tatuya
Internet Systems Consortium, Inc.