Verifying the Disk I/O Scheduler on Linux 8 and Later Systems

Disk I/O schedulers reorder, delay, or merge requests for disk I/O to achieve better throughput and lower latency.

Linux has multiple disk I/O schedulers available, including mq-deadline, none, kyber, and bfq on Oracle Linux 8 and later, RHEL 8 and later, and SUSE Linux Enterprise Server 15 and later systems. You should consult with your storage vendor for the appropriate I/O scheduler configuration to achieve best performance on Oracle Automatic Storage Management (Oracle ASM).

In general, Oracle recommends that you set the I/O Scheduler to mq-deadline for rotating storage devices (HDDs) and to none for non-rotating storage devices such as SSDs and NVMe on Oracle Linux 8 and later, RHEL 8 and later, and SUSE Linux Enterprise Server 15 and later systems.

On all cluster nodes, enter the following command as root to verify the configured disk I/O scheduler value.

cat /sys/block/${ASM_DISK}/queue/scheduler
none [mq-deadline] kyber bfq

In this example, the default disk I/O scheduler is mq-deadline and ASM_DISK is a rotational Oracle ASM disk device.

Note:

Contact your storage vendor for more information about how to configure I/O scheduler on Linux for your storage devices.