Thursday, March 12, 2009

10gR2 RAC on AIX 5L Considerations

On AIX 5L (5.3 ML1 and up) in order to have an optimal rac configuration apply the follwoing settings

Network settings:

ipqmaxlen = 512 (Requires Restart)
rfc1323 = 1
sb_max = 2*udp_recvspac
tcp_recvspace = 65536
tcp_sendspace = 65536
udp_recvspace = 10* udp_sendspace
udp_sendspace = (DB_BLOCK_SIZE * DB_MULTIBLOCK_READ_COUNT) + 4 KB

To find out your settings run as root:

no -a | grep ipqmaxlen
no -a | grep rfc1323
no -a | grep sb_max
no -a | grep tcp_recvspace
no -a | grep tcp_sendspace
no -a | grep udp_recvspace
no -a | grep udp_sendspace

Oracle User Shell Limits

Soft FILE size = -1 (Unlimited)
Soft CPU time = -1 (Unlimited)
Soft DATA segment = -1 (Unlimited)
Soft STACK size -1 (Unlimited)

System Configuration Parameters
Maximum number of PROCESSES allowed for each user > =2048 or 128+PROCESS+PARALLEL_MAX_SERVERS

VMM Settings

AIX large page pool
vmo -p -o lgpg_regions=num_of_large_pages -o lgpg_size=16777216
num_of_large_pages = INT((total_SGA_size-1)/16MB)+1

VMM Settings
minperm% = 5
maxperm% = 90
maxclient% = 90
lru_file_repage = 0
minfree = 960
maxfree = 1088

In order to lock sga into memory
v_pinshm = 1
maxpin% = 80
Usually this is the max value to use, but you can also use ( (size of SGA / size of physical memory) *100) + 3 as more conservative setting.

The set LOCK_SGA=TRUE in spfile or init file.

To find your settings run as root
vmo -a grep lgpg_size
vmo -a grep lgpg_regions
vmo -a grep minperm%
vmo -a grep maxperm%
vmo -a grep maxclient%
vmo -a grep lru_file
vmo -a grep minfree
vmo -a grep maxfree
vmo -a grep v_pinshm
vmo -a grep maxpin%

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