Tuning the I/O scheduler

Use the correct I/O scheduler to increase performance and reduce the possibility of database timeouts when the system is under extreme write load.

About this task

For file systems running on an SSD or in a virtualized environment, use the recommended noop scheduler. On some systems, such as RHEL 8.1+, this is called none.
For additional considerations related to network attached storage, see Databases on storage area networks, network-attached storage, or running in virtualized environments.
For all other systems, use the deadline scheduler.

To determine which scheduler is configured on your system, run the following command.
```
$ cat /sys/block/<block-device>/queue/scheduler
```
To change the scheduler on a running system, run the following command.
```
$ echo '<scheduler name>' > /sys/block/<block-device>/queue/scheduler
```
Example:

In the following example, the system is updated to use the deadline scheduler.
```
$ echo 'deadline' > /sys/block/sda/queue/scheduler
```
To enable the change, restart the system.

The procedure for configuring a scheduler to use at startup depends on the version of Linux. For the correct way to configure this setting, see the system documentation.