I just realised this week that I haven’t really detailed anything about policy managed RAC databases. I remembered having done some research about server pools way back when 126.96.36.199 came out. I promised to spend some time looking at the new type of database that comes with server pools: policy managed databases but somehow didn’t get around to doing it. Since I’m lazy I’ll refer to these databases as PMDs from now on as it saves a fair bit of typing.
So how are PMDs different from Administrator Managed Databases?
First of all you can have PMDs with RAC only, i.e. in a multi-instance active/active configuration. Before 11.2 RAC you had to tie an Oracle instance to a cluster node. This is why you see instance prefixes in a RAC spfile. Here is an example from my lab 188.8.131.52.6 cluster:
DEMO1.__db_cache_size=1073741824 [...] DEMO2.__streams_pool_size=0 *.audit_file_dest='/u01/app/oracle/admin/DEMO/adump' *.audit_trail='db' *.cluster_database=true *.compatible='184.108.40.206.0' *.control_files='...' *.db_block_size=8192 *.db_create_file_dest='+DATA' *.db_domain='' *.db_name='DEMO' *.db_recovery_file_dest='+RECO' *.db_recovery_file_dest_size=4558159872 *.diagnostic_dest='/u01/app/oracle' *.dispatchers='(PROTOCOL=TCP) (SERVICE=DEMOXDB)' DEMO2.instance_number=2 DEMO1.instance_number=1 *.nls_language='ENGLISH' *.nls_territory='UNITED KINGDOM' *.open_cursors=300 *.pga_aggregate_target=310378496 *.processes=300 *.remote_listener='rac11gr2scan.example.com:1521' *.remote_login_passwordfile='exclusive' *.sessions=335 *.sga_target=1610612736 DEMO1.thread=1 DEMO2.thread=2 DEMO1.undo_tablespace='UNDOTBS2' DEMO2.undo_tablespace='UNDOTBS1'
Note that the instance_number, thread and undo tablespace are manually (=administrator) managed. If these aren’t set or configured incorrectly you will run into all sorts of fun. Continue reading