Tuned is a set of tools and a daemon that tunes your system’s settings automatically depending on its usage. It periodically collects data from its components through plugins, which it uses to change system settings according to the current usage.
You can find the system’s tuned profiles used in /lib/tuned/. When you create your own, create them in /etc/tuned in the same way as they are organized in /lib/tuned. I do not recommend creating new profiles in /etc/tuned with the same name as in /lib/tuned, but if you do, the one in the /etc/tuned directory will be used. It is better to create a new one with a different name, including the one you want to modify, and then make the necessary changes to your new profile.
In CentOS/RHEL7, we can use Tuning profiles for setting up the various parameters for tuning. I would recommend this to use as part of configuring Oracle Pre-requisites before Oracle Configuration.
To install and start the tuned service, follow the steps outlined below:
1. First, run the following command to install the required packages:
# yum install -y tuned
2. Enable and start tuned by executing the following commands:
# systemctl enable tuned # systemctl restart tuned
Let’s say you are using Linux kickstart part of your OS standard build and configuring Oracle on top of it, you can implement all basic settings using these tuning profiles. You can customize some parameter settings based on requirements.
| Tuned Parameters | balanced | throughput-performance | tuned-profiles-oracle |
|---|---|---|---|
| I/O Elevator | deadline | deadline | deadline |
| CPU governor | ondemand | performance | performance |
| kernel.sched_min_granularity_ns | auto-scaling | 10ms | 10ms |
| kernel.sched_wake_up_granularity_ns | 3ms | 15ms | 15ms |
| Disk read-ahead | 128KB | 4096KB | 4096KB |
| vm.dirty_ratio | 20% | 40% | 80% |
| File-system barrier | on | on | on |
| Transparent Huge Pages | on | on | off |
| vm.dirty_background_ratio | 10% | 10% | 3% |
| vm.swappiness | 60% | 10% | 1% |
| erergy_perf_bias | Normal | Performance | Performance |
| min_perf_pct(intel_pstate_only) | Auto-scaling | Auto-scaling | Auto-scaling |
| tcp_rmem_default | Auto-scaling | Auto-scaling | 262144 |
| tcp_wmem_default | Auto-scaling | Auto-scaling | 262144 |
| udp_mem(pages) | Auto-scaling | Auto-scaling | Auto-scaling |
| vm.dirty_expre_centisecs | – | – | 500 |
| vm.dirty_writeback_centisecs | – | – | 100 |
| Kernel.shmmax | – | – | 4398046511104 |
| Kernel.shmall | – | – | 1073741824 |
| Kernel.sem | – | – | 250 32000 100 128 |
| fs.file-max | – | – | 6815744 |
| fs.aio-max-nr | – | – | 1048576 |
| ip_local_port_range | – | – | 9000 65500 |
| tcp_rmen_max | – | – | 4194304 |
| tcp_wmen_max | – | – | 1048576 |