How to change SGA in Oracle RAC

How to change SGA in Oracle RAC

This Article for newbie Oracle DBA Since If you trying to change SGA on RAC with wrong way , you may lost your spfile , means you can corrupt your spfile . 

Node One : ORCL1
Node Two : ORCL2

Note : You Need To Check Memory Parameter On Database , if its Have Available Size .

• Connect To Node One :

alter system set sga_max_size=16g scope=spfile sid = 'ORCL1';
alter system set sga_target=12g scope=spfile sid = 'ORCL1';
alter system set sga_max_size=16g scope=spfile sid = 'ORCL2';
alter system set sga_target=12g scope=spfile sid = 'ORCL2';

Or In Another Way :
sql>alter system set sga_target=12G scope=spfile sid='*';
sql>alter system set sga_max_size=16G scope=spfile sid='*';
sql>alter system set sga_max_size=16G scope=spfile ;
sql>alter system set sga_target=12G scope=spfile;

 PGA :

sql>alter system set pga_aggregate_target=4G scope =spfile sid='*';
sql>alter system set pga_aggregate_target=4G scope=both;

• shutdown database PROD (two instances should be shut down)

 $>srvctl stop database -d PROD

$>srvctl START database -d PROD

Check The New Size For Both Instance By :

Show parameter sga ;