Solution for Oracle 11g ORA-00845 in Linux

Environment: CentOS 6.2 + Oracle 11.2.0.3

Problem description: data cannot be started when oracle is installed or when you configure dataguard, error message ORA-00845: MEMORY_TARGET not supported on this system

The main cause of this error is that the tmpfs value is smaller than the memory_target value.

 

[Root @ dac-vm02 ~] # Oerr ora 845.

00845,000 00, "MEMORY_TARGET notsupported on this system"

// * Cause: The MEMORY_TARGET parameter wasnot supported on this operating system or/dev/shm was not sized correctly onLinux.

// * Action: Refer to documentation for alist of supported operating systems. Or, size/dev/shm to be at least theSGA_MAX_SIZE on each Oracle instance running on the system.

Solution:

Therefore, we only need to change the value of tmpfs to a larger value.

Let's take a look at the value of memory_target.

SQL> show parameter memory_target

NAME TYPE VALUE
--------------------------------------------------------------------------------------------------

Memory_target big integer 1296 M

SQL>

You only need to set the tmpfs value to be greater than MB. The initial value of tmpfs is half of the memory size.

Edit the/etc/tmpfs file and set the tmpfs value to 3 GB.

/Dev/VolGroup00/LogVol00/ext3 defaults 1 1
LABEL =/boot ext3 defaults 1 2
Tmpfs/dev/shm tmpfs ults, size = 3G 0 0
Devpts/dev/pts devpts gid = 5, mode = 620 0 0
Sysfs/sys sysfs defaults 0 0
Proc/proc defaults 0 0
/Dev/VolGroup00/LogVol01 swap defaults 0 0

Add the red part, and then mount tmpfs again.

[Root @ Ginna ~] # Umount tmpfs

[Root @ Ginna ~] # Df-h
Filesystem Size Used Avail Use % Mounted on
/Dev/mapper/VolGroup00-LogVol00
28 GB 11G 16G 40%/
/Dev/sda1 99 M 22 M 72 M 24%/boot

[Root @ Ginna ~] # Mount tmpfs

[Root @ Ginna ~] # Df-h
Filesystem Size Used Avail Use % Mounted on
/Dev/mapper/VolGroup00-LogVol00
28 GB 11G 16G 40%/
/Dev/sda1 99 M 22 M 72 M 24%/boot
Tmpfs 3.0G 0 3.0G 0%/dev/shm

OK. After the modification is complete, you can start the Oracle database. However, the change to tmpfs in OEL is somewhat different. You also need to change the/etc/rc. d/rc. sysinit file. For details, see