This post is a quick pocketbook guide on how to implement LARGEPAGES (HUGEPAGES) for Oracle in AIX, a memory configuration that, can result in improved performance across the board for medium to large sized Oracle databases. Implementing LARGEPAGES is fairly simple but, will need a reboot of the AIX Server as well as the Oracle Database itself. The following commands show how to implement LARGEPAGES at 16MB - You have to calculate the amount of lgpg_regions by dividing the total number of bytes by 16777216 (16MB) = 3456 in this case = 54GB:
$ chuser capabilities=CAP_BYPASS_RAC_VMM,CAP_PROPAGATE root
$ lsuser -a capabilities root
$ chuser capabilities=CAP_BYPASS_RAC_VMM,CAP_PROPAGATE oracle
$ lsuser -a capabilities oracle
$ vmo -p -o lgpg_regions=3456 -o lgpg_size=16777216
SQL> alter system set use_large_pages=TRUE scope=spfile sid='*';
SQL> alter system set lock_sga=TRUE scope=spfile sid='*';
The following commands show how to check settings for LARGEPAGES in AIX?
vmo -L lgpg_size
lsuser -a capabilities oracle
vmo -l lru_file_repage
$ svmon
size inuse free pin virtual mmode
memory 29330148 29416756 42342 27409745 26782987 Ded
pg space 15649478 413636
work pers clnt other
pin 24552011 0 2008 849232
in use 26467765 0 232907
PageSize PoolSize inuse pgsp pin virtual
s 4 KB - 2431776 373298 1181576 2565099
m 64 KB - 201562 4303 190125 209497
L 16 MB 3456 3410 0 3456 5131
S 16 GB - 0 0 0 0
$ chuser capabilities=CAP_BYPASS_RAC_VMM,CAP_PROPAGATE root
$ lsuser -a capabilities root
$ chuser capabilities=CAP_BYPASS_RAC_VMM,CAP_PROPAGATE oracle
$ lsuser -a capabilities oracle
$ vmo -p -o lgpg_regions=3456 -o lgpg_size=16777216
SQL> alter system set use_large_pages=TRUE scope=spfile sid='*';
SQL> alter system set lock_sga=TRUE scope=spfile sid='*';
The following commands show how to check settings for LARGEPAGES in AIX?
vmo -L lgpg_size
lsuser -a capabilities oracle
vmo -l lru_file_repage
$ svmon
size inuse free pin virtual mmode
memory 29330148 29416756 42342 27409745 26782987 Ded
pg space 15649478 413636
work pers clnt other
pin 24552011 0 2008 849232
in use 26467765 0 232907
PageSize PoolSize inuse pgsp pin virtual
s 4 KB - 2431776 373298 1181576 2565099
m 64 KB - 201562 4303 190125 209497
L 16 MB 3456 3410 0 3456 5131
S 16 GB - 0 0 0 0