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Slow SLES performance and swapping running Oracle

This document (3445451) is provided subject to the disclaimer at the end of this document.


SUSE Linux Enterprise Server 9 (SLES9)
SUSE Linux Enterprise Server 10 (SLES10)
SUSE Linux Enterprise Server 11
SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server 15


Servers running Oracle databases are experiencing slower performance than expected. Sometimes the server is swapping more than normal. A check of the Asynchronous I/O (AIO) settings shows the following:

# sysctl -a | grep aio
fs.aio-max-nr = 65536
fs.aio-nr = 60416

Sometimes the fs.aio-nr value equals thefs.aio-max-nrvalue. This parameter addresses the use of AIO on a SLES server.


Increase the maximum aio value.

For example, you might add the following to the /etc/sysctl.conf
fs.aio-max-nr = 1048576

NOTE: Depending on your environment, you may need to adjust this value.

Turn on the boot.sysctl service
chkconfig boot.sysctl on

And reboot the server.

Confirm that the increased value has been set properly.No changes to the fs.aio-nr are needed.

Additional Information

For additional recommendations, please review the document:
Oracle9i Real Application Clusters, Quick Installation Guide for Linux x86 (


This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.

  • Document ID:3445451
  • Creation Date: 22-Jan-2007
  • Modified Date:03-Mar-2020
    • SUSE Linux Enterprise Server

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