Re: Allocating more shared memory in Informix/HP-UX 11.0
In article <8ctg5s$31j$1@bcrkh13.ca.nortel.com>, wjjordan@nortelnetworks.com wrote: > In article <8ctb54$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. Actually I read the release notes, and they don't even mention chatr for this version. Appearently shmem_magic is not supported on 64-bit kernel. > > 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. I searched HP's site for patches having to do with Informix, but none of them had anything to do with this version of Informix or our problem. > 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. According to HP-UX documentation for 64-bit implementation: 'SHMEM_MAGIC is an interim solution until 64-bit addressability is available with a true 64-bit kernel. SHMEM_MAGIC will not be supported on future HP implementations of 64-bit architectures (beyond PA2.0). Programs that need larger than 1.75 GB of shared memory on those Architectures will have to be recompiled (as 64-bit executables) for those architectures. Programs that are compiled as 64-bit executables on any 64-bit HP implementation (including PA 2.0) cannot be marked as SHMEM_MAGIC nor do they need to be as they will already have access to more than 1.75 GB of shared memory.' Basically the obsolete chatr options are -n, -q, -M, -N, -l, +l. > 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 ...) I haven't seen anything about this "adb" patch on 11.0 so far. > 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. Another HP feature: Due to OS limitation for Kernel Asynchronous I/O (KAIO) on HP, at present ALL ifnormix shared memory segments are locked in main memory. There is no mechanism to free these segements dynamically other then to disable KAIOON. This is all very new to me and so far I am still in research mode. There is not very much documented information about memory addressing in a 64-bit architecture. Any additional advice would be greatly appreciated. =) > -- > W. Jim Jordan, Nortel Networks, Stop 29CA3A08 | +1 613 763 1568 > PO Box 3511 Stn C, Ottawa, ON K1Y 4H7 Canada | wjjordan@nortelnetworks.com > Opinions expressed are not necessarily those of Nortel Networks. > Inbound spam filtering is in place. Don't send what I won't see. > Sent via Deja.com http://www.deja.com/ Before you buy.