ORA-00845: MEMORY_TARGET not supported on this system

Posted: April 8, 2013 in Database General
Tags: , ,

While starting database on Oracle Linux 5, i got the below error.

[oracle@NODE1]$ sqlplus /nolog

SQL*Plus: Release Production on Mon Apr 8 17:24:02 2013

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

SQL> conn sys as sysdba
Enter password: 
Connected to an idle instance.
SQL> startup
ORA-00845: MEMORY_TARGET not supported on this system

Below are few lines from alert.log file for this error:

Thread 1 advanced to log sequence 115 (LGWR switch)
  Current log# 1 seq# 115 mem# 0: /u02/oradata/YYAPRD/redo01a.log
  Current log# 1 seq# 115 mem# 1: /u03/oradata/YYAPRD/redo01b.log
Mon Apr 08 17:24:12 2013
Adjusting the default value of parameter parallel_max_servers
from 160 to 135 due to the value of parameter processes (150)
Starting ORACLE instance (normal)
WARNING: You are trying to use the MEMORY_TARGET feature. This feature requires the /dev/shm file system to be 
mounted for at least 2046820352 bytes. /dev/shm is either not mounted or is mounted with available space less 
than this size. Please fix this so that MEMORY_TARGET can work as expected. Current available is 1952489472 and 
used is 169725952 bytes. Ensure that the mount point is /dev/shm for this directory.
memory_target needs larger /dev/shm

Well, for this error below is the explanation from oracle:

The new Automatic Memory Management functionality uses /dev/shm on Linux for SGA and PGA management. The errors occur if either MEMORY_TARGET or MEMORY_MAX_TARGET is configured larger than the configured /dev/shm size, or if /dev/shm is mounted incorrectly.

I followed the metalink doc 465048.1 to resolve the issue. But i found a very nice link explaning, what is /dev/shm and what it is used for. This link also contains the solution as suggested by oracle. I thought of mentioning this link here , so that one can get more details about this /dev/shm.


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