Sybase Question:
Download Questions PDF

What is Trace Flags -- 5101 and 5102 in Sybase?

Answer:

5101

Normally, each engine issues and checks for its own Disk I/O on behalf of the tasks it runs. In completely symmetric operating systems, this behavior provides maximum I/O throughput for ASE. Some operating systems are not completely symmetric in their Disk I/O routines. For these environments, the server can be booted with the 5101 trace flag. While tasks still request disk I/O from any engine, the actual request to/from the OS is performed by engine 0. The performance benefit comes from the reduced or eliminated contention on the locking mechanism inside the OS kernel. To enable I/O affinity to engine 0, start ASE with the 5101 Trace Flag.

Your errorlog will indicate the use of this option with the message:

Disk I/O affinitied to engine: 0

This trace flag only provides performance gains for servers with 3 or more dataserver engines configured and being significantly utilized.

Use of this trace flag with fully symmetric operating systems will degrade performance!

Download Sybase Interview Questions And Answers PDF

Previous QuestionNext Question
How to clear a log suspend?What is cmaxpktsz good for in Sybase?