ORA-00845: MEMORY_TARGET not supported on this system and ORA-00093: _shared_pool_reserved_min_alloc must be between 4000 and 0

ORA-00845: MEMORY_TARGET not supported on this system and ORA-00093: _shared_pool_reserved_min_alloc must be between 4000 and 0


Database not coming up due to below errors (ORA-00845: MEMORY_TARGET not supported on this system and ORA-00093: _shared_pool_reserved_min_alloc must be between 4000 and 0)

Scene 1)
##########################################
SQL> startup nomount;
ORA-00845: MEMORY_TARGET not supported on this system
SQL> shut abort
ORACLE instance shut down.
SQL> exitDisconnected


Scene 2)
#########################################
SQL> startup nomount;
ORA-01078: failure in processing system parameters
ORA-00093: _shared_pool_reserved_min_alloc must be between 4000 and 0
SQL> shut abort;
ORACLE instance shut down.
SQL> exit
Disconnected


Scene 3)
#########################################
SQL> startup nomount
ORA-01078: failure in processing system parameters
ORA-00838: Specified value of MEMORY_TARGET is too small, needs to be at least 3072M
SQL>
SQL> exit
Disconnected
#########################################


These are all due to memory Memory related parameter which is not specified as it should be.


Solution:
Scene 1) This error always come if /dev/shm FS size is less then memory targetparameter.
To overcome from this situation either increase the /dev/shm to greater than memory target or keep less value of memory target from /dev/shm.
Other way is to use SGA_MAX_SIZE instead of MEMORY_TARGET.


Scene 2) This error only came if SGA_MAX_SIZE is set but aggregate value of individual memory parameter (db_cache_size, shared_pool_size, java_pool_size, stream_pool_size etc..) value is more than SGA_MAX_SIZE
To overcome from this situation either increase the SGA_MAX_SIZE or decrease aggregate value of individual memory parameter.


Scene 3) in case by mistaken SGA_MAX_SIZE and MEMORY_TARGET both has been define, and SGA_MAX_SIZE is greater than MEMORY_TARGET.
To overcome from this situation remove or keep size 0 either SGA_MAX_SIZE or MEMORY_TARGET parameter value


[oracle@abcdbhost01 dbs]$ sqlplus '"as sysdba"


SQL*Plus: Release 11.2.0.3.0 Production on Wed Sep 10 20:48:05 2014


Copyright (c) 1982, 2011, Oracle. All rights reserved.


Connected to an idle instance.


SQL> startup nomount
ORACLE instance started.


Total System Global Area 3340451840 bytes
Fixed Size 2232960 bytes
Variable Size 771755392 bytes
Database Buffers 2550136832 bytes
Redo Buffers 16326656 bytes
SQL>