Apache2 troubles with shmcb SSLSessionCache...

[Daniel Freedman <freedman@physics.cornell.edu>]

[kindly cc: replies to me]

Hi,

I've searched the Apache and Debian mailing lists and generally
googled for information about this problem, but came up empty.
I'm using apache2 (mpm-prefork) on Debian testing on two different
ia32 machines, with generally similar installs, and exhibiting the
following problem only on one of them (which complicates the problem,
in my analysis).

Namely, apache2 won't start if I include the following line in my
'apache2-modssl.conf' file:

SSLSessionCache shmcb:/var/log/apache2/scache(512000)

I get the following error in my logs:
  [error] Cannot allocate shared memory: (22)Invalid argument

I've read reports on the mailing list of a similar error where it
cannot allocate shared memory as the cache file named in Apache's
"SSLSessionCache" already exists.  In those cases (generally from
unclean shutdowns) it appeared that the solution was easy: just
manually delete the file.

In my case, the file doesn't exist, and I'm getting the "Invalid
argument" error.  Note also, that I've properly installed the Debian
libmm13 package, which appears to be necessary for properly
functioning shmcb, even though this doesn't appear to be widely
documented.  I've also tried to decrease the amount of requested
memory, going as low as 64000, but all to no avail so far.

Any suggestions, please?

Thanks,
Daniel


-- 
Daniel A. Freedman <freedman@physics.cornell.edu>, Graduate Fellow
  Electronic Structure Calculations, LASSP, Cornell University