Home > Workload Solutions > Oracle > Best Practices > Intel-Based Oracle Best Practices on Dell PowerEdge R740 and PowerMax 2000 > Linux Best Practices > Day Three Best Practices > Red Hat Enterprise Linux: Disk Schedulers
In this best practice, we changed the default Linux disk scheduler per Red Hat guidelines.
Category | Operating System |
Product | Red Hat Enterprise Linux 8.3 |
Type of best practice | Performance Optimization |
Day and value | Day 3, Fine Tuning |
Overview
There are several choices for the type of disk scheduler used by the operating system for Red Hat Enterprise Linux 8. The function of the disk scheduler is for ordering I/O requests to storage. Each disk scheduler provides a different method for managing storage requests:
In this best practice, we followed Red Hat’s recommendation of using the none disk scheduler as the PowerMax used NVMe drives and the database access the storage volumes as virtual devices through virtial guest OS and through host bus adapters (HBAs).
Recommendation
The none disk scheduler provided a slight performance increase for the following metrics
The performance metrics below showed no significant changes:
Overall, the none disk scheduler increased storage related performance as reflected in the increase in PowerMax IOPS, NOPM and TPM metrics. There was a very slight drop in write latency on the PowerMax storage array and Log File Parallel Writes which should have improved our IOPS, NOPM and TPM metrics. Although the very slight decrease in write times was not significant, the impact over time can increase performance. We believe this is what was observed in our OLTP load test.
Implementation Steps
To set disk scheduler using TUND:
$ udevadm info --query=property --name=/dev/device | grep -E '(WWN|SERIAL)
[main] Include= existing-profile [disk] devices_udev_regex=ID_WWN=device system unique id elevator=selected-scheduler
To match multiple devices in the devices_udev_regex option, enclose the identifiers in
# tuned-adm profile my-profile
$ tuned-adm active $ tuned-adm verify
Additional Resources
Red Hat Enterprise Linux 8: Monitoring and managing system status and performance