Home > Workload Solutions > Oracle > Best Practices > Intel-Based Oracle Best Practices on Dell PowerEdge R750xs and PowerStore 5000T > Consolidated Best Practices > Red Hat Enterprise Linux: Disk I/O Scheduler
In this best practice, we changed the default Linux disk I/O scheduler per Red Hat guidelines.
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, delaying, or merging I/O requests to storage to achieve better throughput and latency. 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 I/O scheduler as the PowerStore contains NVMe drives and the database access the storage volumes as virtual devices through virtual guest OS and through host bus adapters (HBAs).
Implementation Steps
To set disk I/O scheduler using TUNED, perform the following steps:
$ udevadm info --query=property --name=/dev/device | grep -E '(WWN|SERIAL)'
Use a device name such as sdc to in “–name = /dev/sdc”
2. Create the /etc/tuned/my-profile/tuned.conf configuration file:
[main]
Include= existing-profile
[disk]
devices_udev_regex=ID_WWN=device system unique id
elevator=selected-scheduler
. Replace device system unique id with the value of the chosen identifier (for example,
0x6000c2982a4e742c for /dev/sdc).
To match multiple devices in the devices_udev_regex option, enclose the identifiers in parentheses and separate them with vertical bars. For example, if we have ID_WWN =0x6000c297fc627d0f for /dev/sdd and ID_WWN= 0x6000c2982a4e742c for /dev/sdf, the UDEV entry should look like this:
devices_udev_regex=(ID_WWN=0x6000c297fc627d0f)|(ID_WWN0x6000c2982a4e742c)
elevator=none
3. Enable your profile:
# tuned-adm profile my-profile
4. Verify that the Tuned profile is active and applied:
$ tuned-adm active
$ tuned-adm verify
Additional Resources
Red Hat Enterprise Linux 8: Monitoring and managing system status and performance