ORA-00845: MEMORY_TARGET not supported on this system

This error comes up because you tried to use the Automatic Memory Management (AMM) feature of Oracle 11g R2. Well done, but it seems that your shared memory filesystem (shmfs) is not big enough. So let’s look at the steps necessary to enlarge your shared memory filesystem to avoid the error below.



[oracle@oracle12c bin]$ ./sqlplus /nolog

SQL*Plus: Release 12.1.0.1.0 Production on Tue Aug 06 12:51:43 2013

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

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

$ exit

[root@oracle12c ~]# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg_oracle12c-lv_root

                          50G   18G   30G  37% /

tmpfs                  1002M  480M  522M  48% /dev/shm

/dev/sda1           485M   48M  412M  11% /boot

/dev/mapper/vg_oracle12c-lv_home

                          39G   36G  1.2G  97% /ora

ora                     173G   15G  159G   9% /media/sf_ora

p1                      293G   84G  210G  29% /media/sf_p1

/dev/sr0              55M   55M     0 100% /media/VBOXADDITIONS_4.2.10_84104

[root@oracle12c ~]# mount -t tmpfs shmfs -o size=1g /dev/shm

[root@oracle12c ~]# df -h

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg_oracle12c-lv_root

                           50G   18G   30G  37% /

tmpfs                  1.0G     0  1.0G   0% /dev/shm

/dev/sda1           485M   48M  412M  11% /boot

/dev/mapper/vg_oracle12c-lv_home

                          39G   36G  1.2G  97% /ora

ora                     173G   15G  159G   9% /media/sf_ora

p1                      293G   84G  210G  29% /media/sf_p1

/dev/sr0              55M   55M     0 100% /media/VBOXADDITIONS_4.2.10_84104

shmfs                 1.0G     0  1.0G   0% /dev/shm

shmfs                 1.0G     0  1.0G   0% /dev/shm

To make the change presistent edit yout /etc/fstab file to include the option you specified.

[root@oracle12c ~]# cat /etc/fstab
[..]
tmpfs     /dev/shm   tmpfs   size 1g  0 0
[..]

[oracle@oracle12c bin]$ ./sqlplus /nolog

SQL*Plus: Release 12.1.0.1.0 Production on Tue Aug 06 13:01:19 2013

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

SQL> conn / as sysdba

Connected to an idle instance.

SQL> startup

ORACLE instance started.

Total System Global Area  835104768 bytes

Fixed Size    2293880 bytes

Variable Size  562040712 bytes

Database Buffers  268435456 bytes

Redo Buffers    2334720 bytes

Database mounted.

Database opened.

SQL>