How I/O scheduler parameters can be added for RHEL8.x
Article ID: 388856
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Products
Issue/Introduction
In the Disk I/O Settings section of the Installation Guide for Greenplum, it specifies how to modify the Disk I/O scheduler only for RHEL6 and RHEL7.
This article describes how to change the Disk I/O scheduler in RHEL8 and above.
Resolution
In RHEL 8 and later, the method for configuring I/O schedulers has evolved from previous versions. The traditional elevator kernel parameter, which was commonly set using tools like grubby in RHEL 6 and 7, is deprecated in RHEL 8. Instead, RHEL 8 introduces multiqueue I/O schedulers, such as mq-deadline, none, kyber, and bfq. The default scheduler is typically mq-deadline.
See Setting the disk scheduler in the RedHat documentation for more details on the scheduler and how it can be set for individual devices.
In general, keeping the default I/O scheduler will be OK. For HDD use mq-deadline and for NVMe use none.
Further details and information can be found in:
- RedHat KB What is the suggested I/O scheduler to improve disk performance when using Red Hat Enterprise Linux with virtualization?
- Dell Best Practices: Red Hat Enterprise Linux: Disk I/O Scheduler
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