SUMMARY: What happens when shmmax is set above MAXINT on 2.6?

Many thanks to Casper Dik, Rich Teer, and especially Michael Schulte for
reminding me of some simple arithmetic.

My question (paraphrased):

My group has an E6500 server running Solaris 2.6 with the shmmax kernel
parameter set to 6 GB. The system boots and is running just fine; however,
sysdef reports that shmmax is set to 2GB. I wanted to know if this would /
could cause problems other than performance degradation, and I also was
curious as to how the OS arrived at 2GB.

Basic answers:

Shouldn't be an issue with the system (and we'll fix it next time we get a
chance). With regards to the 2 GB value, the system apparently chopped off
the high-order bit. 6 GB = 2^32 + 2^31, after shifting the high-order bit
you get 2^31 = 2 GB. I knew I was missing something simple.

Thanks once again!


==========================================
Allen Cain MP 5H - C
System Administrator
IS / Application Server Engineering
Tennessee Valley Authority
==========================================

[1053 byte] By [CodeProf.com] at [2007-12-25 0:25:00]