Sun Java System Messaging Server 6.3 Administration Guide

To Specify Message Store Database Snapshot Interval and Location

There should be five times as much space for the database and snapshots combined. It is highly recommended that the administrator reconfigure snapshots to run on a separate disk, and that it is tuned to the system’s needs.

If stored detects a problem with the database on startup, the best snapshot will automatically be recovered. Three snapshot variables can set the following parameters: the location of the snapshot file, the interval for taking snapshots, number of snapshots saved. These configutil parameters are shown in Table 20–13.

Having a snapshot interval which is too small will result in a frequent burden to the system and a greater chance that a problem in the database will be copied as a snapshot. Having a snapshot interval too large can create a situation where the database will hold the state it had back when the snapshot was taken.

A snapshot interval of a day is recommended and a week or more of snapshots can be useful if a problem remains on the system for a number of days and you wish to go back to a period prior to the point at which the problem existed.

stored monitors the database and is intelligent enough to refuse the latest snapshot if it suspects the database is not perfect. It will instead retrieve the latest most reliable snapshot. Despite the fact that a snapshot may be retrieved from a day ago, the system will use more up to date redundant data and override the older snapshot data, if available.

Thus, the ultimate role the snapshot plays is to get the system as close to up-to-date and ease the burden of the rest of the system trying to rebuild the data on the fly.

Table 20–13 Message Store Database Snapshot Parameters



Location of message store database snapshot files. Either existing absolute path or path relative to the store directory.

Default: dbdata/snapshots

Minutes between snapshots. Valid values: 1 - 46080 

Default: 1440 (1440 minutes = 1 day)

Number of different snapshots kept. Valid values: 2 -367 

Default: 3