Oracle's 11g Automatic Storage Management on CentOS 5 (x86_64)
Command "ipcs -m" appears to be almost useless for getting Oracle 11g shared memory
The basic steps for shared memory monitoring and tuning /dev/shm to handle instances with MEMORY_TARGET more then 1024M had been explained in Tanel Poder’s blog ().
Posting bellow follows advices from Tanel Poder’s blog to build Oracle 11g (64 bit) ASM database with MEMORY_TARGET 1.1 GB on CentOS 5 .
Changes have been made to SPFILE after database install. Restarting database I've got "ORA-00845: MEMORY_TARGET not supported on this system" due to insufficient size
of tmpfs. View  regarding definition of MEMORY_MAX_TARGET and MEMORY_TARGET.
I've tuned OS configuration files and oracle shell environment for 64 bit Oracle 11g as advised in  for 32 bit Oracle 11g .
# rpm -Uvh oracleasm-2.6.18-8.el5-2.0.4-1.el5.x86_64 \
# /etc/init.d/oracleasm configure
# /etc/init.d/oracleasm enable
Create ASM disks as requiered (for example):-
# /etc/init.d/oracleasm createdisk VOL1 /dev/sda7
# /etc/init.d/oracleasm createdisk VOL2 /dev/sda8