Question & Answer
Question
When File system cache is turned off for DB2 Table spaces, I/O is done via Concurrent I/O ( CIO ) or Direct I/O ( DIO ) requests. When alignment or size conditions for the I/O are not met , then those I/O requests can result in demoted I/O requests, which are relatively expensive to process by the OS. This can impact overall DB2 performance. This technote will discuss methods for detecting whether this is happening.
[{"Product":{"code":"SSEPGG","label":"Db2 for Linux, UNIX and Windows"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Component":"Performance - General\/Tuning","Platform":[{"code":"PF002","label":"AIX"}],"Version":"9.8;9.7;9.5;9.1","Edition":"Advanced Enterprise Server;Enterprise Server;Express;Express-C;Personal;Workgroup Server","Line of Business":{"code":"LOB10","label":"Data and AI"}}]
Log InLog in to view more of this document
This document has the abstract of a technical article that is available to authorized users once you have logged on. Please use Log in button above to access the full document. After log in, if you do not have the right authorization for this document, there will be instructions on what to do next.
Was this topic helpful?
Document Information
Modified date:
04 June 2026
UID
swg21469603