ORA-27101: Shared memory realm does not exist Shared memory realm is not available on the system.
One of the reasons is that there was not enough memory available to create a shared memory segment.
If this is the case the alert.log should contains a message indicating this.
On Unix this might be indicating that some kernel parameters are set too low (SHMMAX, SEMMNI, ...).
A previous shared segment that was not cleaned up correctly might also exist.
Check with you Unix engineer for possible causes/fixes.
Some useful Unix commands can be: ipcs -s, ipcrm -s, kmtune -q, ...
Another possibility is that the init.ora or spfile is missing, thus disallowing the database from starting up.
 Forum Messages
[oracle@xxx bin]$ sqlplus
SQL*Plus: Release 10.2.0.1.0
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Enter user-name: / as sysdba
Connected to an idle instance.
SQL> startup
ORA-44410: XE edition single instance violation error
SQL*Plus: Release 10.2.0.1.0
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Enter user-name: test/test
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
Linux Error: 2: No such file or directory
ipcs
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x880f3334 98307 oracle 640 134221824 13
------ Semaphore Arrays --------
key semid owner perms nsems
0x0f9b5efc 557068 oracle 640 44
0x92d30344 2949133 oracle 640 44
------ Message Queues --------
key msqid owner perms used-bytes messages
[oracle@id91197 bin]$ sysresv
IPC Resources for ORACLE_SID "XE" :
Shared Memory
ID KEY
No shared memory segments used
Semaphores:
ID KEY
2949133 0x92d30344
Oracle Instance not alive for sid "XE"
--> 2 Semaphores detected by ipcs, but only one detected by sysresv
ipcrm -s 557068
sqlplus /
SQL*Plus: Release 10.2.0.1.0
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Enter user-name: as sysdba
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 134217728 bytes
Fixed Size 1257620 bytes
Variable Size 58724204 bytes
Database Buffers 71303168 bytes
Redo Buffers 2932736 bytes
Database mounted.
Database opened.
sysresv
IPC Resources for ORACLE_SID "XE" :
Shared Memory:
ID KEY
557059 0x679eb6dc
Semaphores:
ID KEY
3244044 0x92d30344
Oracle Instance alive for sid "XE"
ipcs
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x679eb6dc 557059 oracle 640 134221824 13
------ Semaphore Arrays --------
key semid owner perms nsems
0x92d30344 3244044 oracle 640 44
------ Message Queues --------
key msqid owner perms used-bytes messages
|
| I HAVE ORACLE 10G INSTALLED ON UNIX SERVER. IT HAS TWO DATABASES. CURRENTLY ONLY ONE IS BEING USED.ALL WORKS FINE BUT SUDDENLY IN MID OF OPERATIONS BEING PERFORMED ON DATABSE SUDDENLY IT THROWS THE ERROR : ORACLE NOT AVAILABLE, SHERD MEMORY REALM DOES NOT EXIST. BUT AFTER SOMETIME IT STARTS AUTOMATICALLY. ANY REASON WHY DOES IT HAPPEN SO? |
| : -> 26-MAY-2008 08:56:59 | Check alert.log | DbMotive | Reply |
| You need to check your alert.log file, this might contain additional messages as why this happens |
| ORA-27101: Shared memory realm does not exist, after restarting the system this problem has been occured. |
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