Re: [rtl] regd mbuff

[Matt Sherer <chaos@emerging.org>]

"Basham, Richard R" wrote:
> 
> Here is an exchange I had with Tomasz a while back regarding mbuff and buffer sizes.  I am not sure if this is the definitive answer but it may help a few people out.
> 
> It is a little long winded but it covers a lot of investigation effort.

...

> 
> I checked SHMAX and yes indeed it is set to 32 MB.  It says in the file not to change that value >because so many others depend on that value.  Therefore I will not change that value.

AFAIK, modifying SHMMAX via sysctl is perfectly safe, although I don't
know if it affects the problem you're seeing.  Don't bother with
changing the source, just echo a new val (in bytes) to
/proc/sys/kernel/shmmax.  I've found it to be safe at 700 megs, which
was used to help Oracle chew through large data sets.  I believe there
is a maximum on the size at around a gig, but I'm not sure where that is
documented. (If it is documented.)

--Matt Sherer