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40 Sizing and Best Practices for Online Transaction Processing Applications with Oracle 11g R2 using Dell PS Series | BP1003
7.4 Oracle database application
7.4.1 Database volume layout
The following are database volume layout best practices:
 Oracle recommends using ASM for simplified administration and optimal I/O balancing across disk
groups.
 ASM external redundancy is preferred while configuring ASM disk groups. There is no need to use
other types of redundancy because the PS Series array will provide the required redundancy.
 Use same-sized ASM disks within ASM disk groups. This helps Oracle ASM to optimally perform load
balancing.
 Map storage volumes to individual ASM disks and create separate ASM disk groups for database
data files, temporary data files, and transactions logs.
 Create a separate tablespace for database data files and temporary database files, ensuring hosting
on respective ASM disk groups.
7.4.2 Oracle AMM
The following are Oracle AMM best practices:
 The Oracle AMM feature assigns MEMORY_TARGET to be 40% of the total physical memory on the
server. Based on the test results described in section 6.1, setting MEMORY_TARGET to a value 50%
to 60% of the total server memory can be used as a guideline for TPC-E like workloads. The memory
setting can vary based on various database factors, so careful monitoring and analysis should be
done before tuning this parameter.
 The Oracle AMM feature requires the /dev/shm file system size to be at least equal to the value of the
MEMORY_TARGET parameter. By default, the size of this file system will be set to 50% of the total
physical memory.
 You need to change the size of the /dev/shm file system to support custom MEMORY_TARGET
settings. Make sure that the database instances are shut down before making any changes to the
size of /dev/shm. You can use the mount command as shown in the following command, which
allows the MEMORY_TARGET value to be set up to 64 GB.
[root@oranode1 oswbb]# mount -t tmpfs shmfs -o size=65g /dev/shm
 Verify that the size of the /dev/shm file system is modified using the following command.
[root@oranode1 oswbb]# df -k
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/vg_oranode1-lv_root
51606140 26696252 22288448 55% /
tmpfs 68157440 0 68157440 0% /dev/shm
/dev/sda1 495844 68132 402112 15% /boot
/dev/mapper/vg_oranode1-lv_home
201585632 195108 191150524 1% /home
shmfs 68157440 0 68157440 0% /dev/shm