12c Database multiple shared memory id - which to remove

Zach W-Oracle

Hi

We have issue starting up our db instance.

SQL> startup

ORA-01012: not logged on

Process ID: 0

Session ID: 0 Serial number: 0

and

Total /dev/shm size: 15087755264 bytes, used: 11739136 bytes

Shared Memory:

ID       KEY

309854210    0x00000000

309886979    0x00000000

309821441    0x00000000

309919748    0xd9f9bcac

Semaphores:

ID       KEY

425987     0x92743d84

458756     0x92743d85

491525     0x92743d86

Oracle Instance not alive for sid "PPPP"

What steps can we perform to know which Shared Memory ID to remove the orphaned shared memory segment ?

Any help is appreciated