[ale] Postgress + Slony + Reiser logfile limit

Michael H. Warfield mhw at wittsend.com
Fri Apr 28 20:49:59 EDT 2006


On Fri, 2006-04-28 at 16:31 -0400, Randy Ramsdell wrote:
> Ok hopefully someone knows about this.

> We have Slony running for Postgress replication. Both master and slave 
> are running on Suse 9.3.

> Once the log file  for the replicated data grows > than 2gig, logging 
> stops.  Neither system  has a 2gig limit, so I cannot figure out where 
> the problem exists.

> Has anyone seen this before?

	No, and, yes...  Sort of.  Not with Postgresql and replication but
elsewhere, certainly.

	It's a little more complicated than just the system support and file
system support for files greater than 2 Gig.  The applications have to
have some twiddling as well, especially if (but not only if) they have
provisions for lseek().

	I ran into this with TCT (The Coroner's Toolkit).  It's basically a
gigantic perl script hairball.  Some of the forensic BCDs I was using
had full support for files over 2Gig but the perl interpreter was NOT
patched for llseek() and consequently blew chunks when an output image
file hit the 2 Gig limit or when it tried to process a disk image file
greater than 2 Gig.  That was several years ago and I believe it's been
patched for perl.  I've also run into this with tcpdump (-w output
option) and even redirecting stdout to a file (bash).  I'm sure there is
still more of that out there.

	My guess as to where the problem is...  In postgresql.  It's file
handling for that log has probably not been patched to handle log files
greater than 2Gig (even if it's just appending to it).

	Mike
-- 
Michael H. Warfield (AI4NB) | (770) 985-6132 |  mhw at WittsEnd.com
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