Re: Allocating more shared memory in Informix/HP-UX 11.0
From: wjjordan@nortel.ca (Jim Jordan) > >In article <8ctb54$t4$1@news.xmission.com>, >Obnoxio The Clown <obnoxio@hotmail.com> wrote: > > > >From: query_gurl@my-deja.com > >> > >>Are there any available patches that can be applied to Informix Dynamic > >>Server 7.31.FC2 that would help in allocating more shared memory? > >> > >>Currently we are running Informix on a HP-UX 11.0 Server with 4 gigs of > >>RAM. The 4 gigs of RAM is recognized by HP-UX, but Informix chokes > >>trying to allocate more then 800 meg. We think the problem lies in > >>allocating memory across quadrants. > >> > >>If possible we would like for Informix to be able to use 2.75 gigs of > >>RAM. If anyone can point me in the right direction that would be great! > > > >chatr is the right direction. There should be stuff in your release >notes. > >You must have missed it. > >The Informix release notes for HP-UX are traditionally somewhat thin. >You'll do better searching the HP support site for patches that >explicitly mention Informix. Informix only release-notes the stuff they >had to fiddle with to pass their QA suite. > >You're on 11.0, so some things will be different from our experience. >We're on 10.20 with the SHMEM_MAGIC kernel and utilities patch so we can >get 2.75 GB of shared memory from the box. > >In 10.20 we had to chatr -M almost everything in $INFORMIXDIR/bin, and >set shmmax to 1GB (2**30, not 10**9). Even then, all we could grab for >cache is 970000 pages, or just under two full segments. As our fine >clown mentioned, you'll probably have to run chatr -M in 11.0 as >well--Informix comes tagged EXEC_MAGIC, not SHMEM_MAGIC, out of the box. > >Make sure that you're using best-fit, not first-fit, shared memory >allocation. In 10.20 this is an adb patch to the running system at >start-up. Not sure what this looks like in 11.0. (Another 10.20 >gotcha: best-fit only works in two quadrants, and not the extra one >that SHMEM_MAGIC can use ...) > >Watch for memory fragmentation. If RESIDENT is -1, and you bounce the >server a lot, HP-UX 10.20 and 11.00 get very slow in locking memory. >We've used Glance to measure one call to shmctl at over 6 minutes. HP's >workarounds: either don't bounce the server, or reboot. A brilliant exposition, both of how to set up the bigger memory and also of why I'll be sticking to Sun for a while. :-) ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com