看問題比較迷惑人，什麼是不支援

從oracle 11g開始引入了MEMORY_TARGET，當它的值大於/dev/shm的值時就會丟擲ORA-00845

官方解釋是：

Starting with Oracle Database 11g, the Automatic Memory Management feature requires more shared memory (/dev/shm)and file descriptors. The size of the shared memory must be at least the greater of the MEMORY_MAX_TARGET and MEMORY_TARGET parameters for each Oracle instance on the computer. If the MEMORY_MAX_TARGET parameter or the MEMORY_TARGET parameter is set to a nonzero value, and an incorrect size is assigned to the shared memory, it results in an ORA-00845 error at startup. On Linux systems, if the operating system /dev/shm mount size is too small for the Oracle system global area (SGA) and program global area (PGA), it results in an ORA-00845 error.

看樣子如果SGA和PGA加起來比/dev/shm大也會導致ORA-00845

解決辦法：

vi /etc/fstab

tmpfs                   /dev/shm                tmpfs   defaults,size=8G        0 0

這裡的size是要根據MEMORY_TARGET或者SGA+PGA得到，一定要比MEMORY_TARGET或者SGA+PGA大才行。

mount -o remount /dev/shm生效