Technical Bulletin Number 56

Improving ClearCase Performance with Network Appliance NAS Devices

Rational and Network Appliance have identified and corrected several problems that could affect the performance of ClearCase on UNIX VOB or view server hosts that use a Network Appliance NAS device for VOB or view database storage. We recommend that all sites using this configuration upgrade their Network Appliance NAS devices to Data ONTAP operating system release 6.3.2 or later. (Rational currently recommends using Data ONTAP release 6.4).

If you are not sure that your system is experiencing these problems, take the following steps:

• Create a db.conf file in the /var/adm/atria/config directory. The file must include a line of the form

  - locks_held 15

• After a day or two, check the db_server_log file. If it shows repeated lock held intervals of approximately 35, 60, or 120 seconds, upgrading the NAS device to the recommended operating system release will improve ClearCase performance.

Rational is preparing a white paper that describes additional ways to identify and correct performance problems related to NAS devices. We expect it to be available soon in the white papers section of the ClearCase customer Web site.

Any Questions?

If you have any questions regarding the situations discussed in this Technical Bulletin, please contact Rational Customer Support via telephone, fax, or electronic mail as described below. For information regarding support hours, languages spoken, or other support information, click the Technical Support link on the Rational Web site at www.rational.com.

Technical Bulletin Number 56 - 4/18/03