If you use SGA = 17 GB , shmall should be 4456448 ). If you set it less than ... you will see SQL> startup ORA-27102: out of memory Linux-x86_64 Error: 28: No space left on device http://surachartopun.com/2009/10/shared-memory-tuning-startup-database.html If you're finding out other doc (except doc 301830.1) Tuning Red Hat Enterprise Linux: Oracle and Oracle RAC<http://www.redhat.com/f/pdf/summit/scroft_240_turning_rhel_for_oracle.pdf> mem=$(free|grep Mem|awk '{print$2}') totmem=$(echo "$mem*1024"|bc) huge=$(grep Hugepagesize /proc/meminfo|awk '{print $2}') max=$(echo "$totmem*75/100"|bc) all=$(echo "$max/$huge"|bc) echo "kernel.shmmax = $max" echo "kernel.shmall = $all" >Sizing shmall to be the SUM of the SGAs on the server makes sense, but I'm curious if anyone has experience that suggests otherwise? Also, can anyone think of a good reason to set shmall to RAM + swap (other than "'cuz it's there")? I don't use SWAP to calculate. I use only Physical memory. and SWAP is DISK anyway. Good Luck Surachart Opun http://surachartopun.com On Tue, Jan 12, 2010 at 10:54 PM, Herring Dave - dherri < Dave.Herring@xxxxxxxxxx> wrote: > Folks, I've inherited a 4-node RAC plus DG environment that has a rather > curious shmall setting that I'd appreciate your thoughts on. I've done my > best to understand it's current setting but those that made the decision are > no longer with the company and/or client. > > The system is running 10.2.0.2 on RHEL 4. Like I said, it's a 4-node RAC, > 64 GB RAM, with the same for a physical standby. Currently the SGA of each > instance is 17 GB. > > The install guide gives a minimum value of 2097152 (8 GB) while the current > value is 25165824 (96 GB). To me it seems just a wee bit aggressive to be > setting the total shared memory to be RAM + swap! MOS doc 301830.1 gives > the recommendation of the SUM SGAs on the server, so in this case 4456448 > (17 GB). > > Sizing shmall to be the SUM of the SGAs on the server makes sense, but I'm > curious if anyone has experience that suggests otherwise? Also, can anyone > think of a good reason to set shmall to RAM + swap (other than "'cuz it's > there")? > > Thx. > > Dave Herring | DBA, Acxiom Database Services > > 630-944-4762 office | 630-430-5988 cell | 630-944-4989 fax > 1501 Opus Pl | Downers Grove, IL, 60515 | U.S.A. | www.acxiom.com > Service Desk: 888-243-4566 > > > > *************************************************************************** > The information contained in this communication is confidential, is > intended only for the use of the recipient named above, and may be legally > privileged. > > If the reader of this message is not the intended recipient, you are > hereby notified that any dissemination, distribution or copying of this > communication is strictly prohibited. > > If you have received this communication in error, please resend this > communication to the sender and delete the original message or any copy > of it from your computer system. > > Thank You. > > **************************************************************************** > > -- > //www.freelists.org/webpage/oracle-l > > >