Hi Am trying to setup Oracle's Automatic Shared Memory Mgmt (ASMM) on Solaris 9 (and 10) and having some issues. Not sure if it is (i) bug with Oracle (ii) bug with Solaris 9, (iii) I screwed up or (iv) my understanding/assumption is wrong O/S: Solaris 9(SPARC) Oracle: 10.1.0.4 (64bit) spfile has: SGA_MAX_SIZE=500M SGA_TARGET=200M I thought that with the above, oracle will startup with 200M SGA and _only_ 200M of System memory is allocated. You then have the ability to dynamically increase it (using ALTER SYSTEM SET sga_target=xxx ) up to SGA_MAX_SIZE. Q. Is the above assumption correct? Some stats and information # ------------------------------------- # Get Memory Information from Oracle # ------------------------------------- % sysresv OEM10G IPC Resources for ORACLE_SID "OEM10G" : Shared Memory: ID KEY 7040 0x629dc97c ^^^^ Semaphores: ID KEY 4718614 0xdf751d7c Oracle Instance alive for sid "OEM10G" # ------------------------------------- # Get Memory allocated to Oracle # ------------------------------------- % ipcs -a | grep 7040 m 7040 0x629dc97c --rw-r----- oracle dba oracle dba 18 524296192 19547 23979 15:22:46 15:22:46 14:59:24 ^^^^ ^^^^^^^^^ Notice that it has allocated 500M of memory. I was expecting it to be 200M % ps -ef | grep dism root 23069 1 0 14:59:25 ? 0:00 ora_dism_OEM10G THis shows Oracle's DISM is running. Q1. When you set SGA_MAX_SIZE=500M and SGA_TARGET_SIZE=200M, on startup does Solaris allocate 200M or 500M? # ========================== # More information # ========================== SQL> show sga Total System Global Area 524288000 bytes Fixed Size 1303456 bytes Variable Size 388242528 bytes Database Buffers 134217728 bytes Redo Buffers 524288 bytes SQL> show parameter sga NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ lock_sga boolean FALSE pre_page_sga boolean FALSE sga_max_size big integer 500M sga_target big integer 200M Q2. Does setting SGA_MAX_SIZE make the Shared Memory non-pagable? see reply from Howard Rogers & Nuno http://www.webservertalk.com/archive149-2004-8-333787.html Also Oracle's manual - http://download-west.oracle.com/docs/html/B10812_01/appendix_e.htm#sthref830 Intimate Shared Memory On Solaris systems, Oracle Database uses Intimate Shared Memory (ISM) for shared memory segments because it shares virtual memory resources between Oracle processes. ISM causes the physical memory for the entire shared memory segment to be locked automatically. On Solaris 8 and Solaris 9 systems, dynamic/pageable ISM (DISM) is available. This enables Oracle Database to share virtual memory resources between processes sharing the segment, and at the same time, enables memory paging. The operating system does not have to lock down physical memory for the entire shared memory segment. Q3. How does one proof or disproof that Solaris has Dynamic memory allocation enabled? PS: System has been patch and read the following refernece Enabling Dynamic SGA on Solaris platform - Doc ID: 151222.1 SUN bug. 4675878