DCC build options for performance and sizing

Gary Mills mills@cc.umanitoba.ca
Wed Jun 9 22:11:15 UTC 2010

On Wed, Jun 09, 2010 at 09:29:30AM -0500, Gary Mills wrote:
> On Wed, Jun 09, 2010 at 01:33:21PM +0000, Vernon Schryver wrote:
> > 
> > If the system has enough RAM to contain the hash table of dcc_db.hash
> > and the recent part of dcc_db, then the best tactic is the work-around
> > for Solaris's lack of mmap(MAP_NOSYNC).  That -around is to move
> > dcc_db.hash (but of course not dcc_db) to a memory mapped file system.
> > /tmp is often a RAM file system on Solaris systems, so adding -H/tmp
> > to DBCLEAN_ARGS in dcc_conf should be effective.
> Yes, I read about that.  I was reluctant to change so many things at
> the same time.  It's not a good idea for system processes to create
> files in /tmp because that's a publically-writable directory.
> /var/run is a better choice.  The startup script would have to create
> /var/run/dcc, for example, and make it owned by the DCC user.  I assume
> it doesn't already do that.

I see that it actually does create that directory, but only for startup
of dccm and dccifd.  I've added code to do that to my all-purpose
startup script so that dccd can use that directory too.  The migration
on my test system was flawless.

-Gary Mills-        -Unix Group-        -Computer and Network Services-

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