Performance Advice from a Mysterious Friend, Part 4
April 9, 2008 Ted Holt
I’ve already published three performance tips from one of your fellow subscribers, a consultant who has found these techniques to be helpful. Here’s tip number 4.
Our friend’s advice: “Use journal cache support.”
Journal caching is similar to file buffering. Caching directs the system to cache journal entries in main storage before flushing them to disk. You do not get journal caching automatically. It is a separately chargeable feature of i5/OS.
The performance advantage is like that of buffering files. Normally the system writes a journal entry to the journal receiver before continuing with the next I/O operation. Caching allows the system to continue with the next I/O before the journal entry is written to disk.
The V5R3 Information Center lists several advantages of journal caching and gives recommendations for when journal caching should and should not be used.