System Configuration

Review the following:

• Exadata Component Configuration
  
• Database Configuration
  

Exadata Component Configuration

Table A-1 Exadata Components and Configuration

Component	Configuration
Exa check	Run the Exachk utility and verify the adherence to the recommended Exadata best practices. For more information, see article ID 1070954.1 on My Oracle Support (https://support.oracle.com).
RAC	Use defaults and native load balance.
High performance disks	We recommend 15000 revolutions per minute (RPM) high performance disks.

Database Configuration

Review the following:

• Database I/O Calibration
  
• Resource Manager
  
• Database Parameters
  
• Parallel Degree Policy
  
• Oracle Automatic Stats Job
  
• Tablespace and Redo Log Recommendations
  
• ASM Recommendations
  
• Maximum Availability Recommendations
  

Database I/O Calibration

Run the I/O calibration tool for each database to set the automatic degree of parallelism.

For more information on I/O calibration and automatic degree of parallelism, see the I/O Calibration Inside the Database section in the Oracle 12.2 Database Performance Tuning Guide as well as article IDs 727062.1 and 1269321.1 on My Oracle Support (https://support.oracle.com).

Resource Manager

Use the Oracle Resource Manager to manage and prioritize the resource allocation for different applications, databases, instances, users, and so on.

For more information, see article ID 1339769.1 on My Oracle Support (https://support.oracle.com) and the White Paper Using Oracle Database Resource Manager.

Database Parameters

Table A-2 Recommended Settings for Database Parameters

Database Parameter	Recommended Settings
processes	1500
parallel_max_servers	500-1280
parallel_min_servers	128
parallel_degree_policy	LIMITED
parallel_adaptive_multi_user	TRUE
parallel_degree_limit	CPU
parallel_force_local	FALSE
sga_target	40 GB
sga_max_size	40 GB
pga_aggregate_target	If HugePages is used, set this parameter to 20 GB. Else, set it to 12 GB.
memory_target	If HugePages is used, set this parameter to 0. Else, set it to 60 GB.
memory_max_target	If HugePages is used, set this parameter to 0. Else, set it to 60 GB.
db_block_size	8192
workarea_size_policy	AUTO
db_cache_size	2 GB
shared_pool_size	2 GB
optimizer_secure_view_merging	False
_px_join_skew_handling	FALSE
result size max	0
_optimizer_dsdir_usage_control	0

Parallel Degree Policy

Set the parallel_degree_policy parameter to LIMITED to use the automatic degree of parallelism and smart scans.

• The Omics Data Bank (ODB) application uses Exadata SQL processing innovations. Setting this parameter to LIMITED disables the in-memory parallel execution that leads to better use of smart scans.
• Statement queuing is disabled to avoid any waits under heavy load where there are chances of draining all PX servers thereby impacting response times.

Parallel Degree Limit

Set the parallel_degree_limit parameter to CPU or below to improve the response time. A resource-intensive query may request too many PX servers, draining available resources. Use the Resource Manager to limit the resource allocation to intensive or long running processes.

Adaptive Tuning

Set the parallel_adaptive_multi_user parameter to TRUE, which lets Oracle downgrade PX requests under stress. You should not over-burden the database CPUs by allocating all requested PX servers, especially when the database nodes are running at over 80% CPU load.

Alternatively, you can use the Resource Manager to control resources.

Parallel Max Servers

Set the parallel_max_servers parameter between 500-1280 to make sure that there are enough PX server processes to allocate to concurrent user requests. In benchmark tests, this was set to 512.

Parallel Min Servers

Set the parallel_min_servers parameter to CPU to ensure the availability of a specific number of PX server processes at startup.

Memory Settings

Set the Automatic Memory Management (AMM) using the memory_target parameter to 60 GB.

Also, you have to set the Program Global Area (PGA) (pga_aggregate_target parameter) to a minimum of 20/10 GB depending upon whether HugePages is used and the System Global Area (SGA) (sga_max_size parameter) to a minimum of 40 GB.

Note:

If you use HugePages, set all DB memory parameters appropriately as AMM does not work with HugePages. If you encounter any shared pool issues with HugePages, switch to alternate recommended settings.

Processes

Set the processes parameter to a sizeable number based on the expected concurrency. The minimum value should be 1024. In internal benchmarks, it was set to 2000 based on concurrent loads.

Oracle Automatic Stats Job

Disable the Oracle Automatic Stats job if it is configured.

Automatic statistics scheduler jobs run under different maintenance windows (such as daily, weekly, and so on). This may potentially generate bad statistics due to data availability (for example, the application may have transient data or no data in stage tables).

Tablespace and Redo Log Recommendations

Table A-3 Tablespace Recommendations

Tablespace	Recommended
TEMP	500 GB across all nodes.
UNDO	500 GB per instance.

Note:

Use the BigFile tablespace for TEMP, UNDO, and user (HDI, HDM, HCD, CDM, and ODB) tablespaces to ease tablespace maintenance.

Configure the redo logs to have at least five groups per instance with each member having a size of 500 MB or higher.

ASM Recommendations

Redundancy - Oracle uses NORMAL redundancy for all benchmarks. You can use HIGH redundancy as per the data mirroring requirements. However, note that the usable storage is lower when using ASM with HIGH redundancy disk groups.

ASM AU Size - We recommend you use the default setting for the disk sequential reads.

Maximum Availability Recommendations

You may want to consider the recommendations in the White Paper Best Practices for Database Consolidation on Exadata Database Machine .