When a database starts running on a database server, SQL Anywhere reports the number of file fragments for the main database file, as reported by the operating system. Excessive disk fragmentation of the disk volume that holds the database can cause performance problems because fragmentation can lead to additional disk latency during I/O operations.
The problem of file system fragmentation is independent of table page fragmentation within the database. The analysis and resolution of these separate problems are performed using different methods and tools. The number of file fragments is reported only for Windows-based SQL Anywhere database servers. Unix file systems, including Linux file systems, incur significantly fewer fragmentation issues than Windows-based systems.
On Windows platforms, database files generally consist of more than one fragment. When you receive this message for a database, the number of fragments relative to the size of the database file helps you determine whether the system administrator needs to take any action. For example, a 100 GB database file that is composed of 25 fragments should not be considered a serious problem, but a 50 MB database file consisting of 300 disk fragments may be affected by performance problems. To eliminate file fragmentation problems, put the database on a disk partition by itself and then periodically run one of the available Windows disk defragmentation utilities.
Discuter à propos de cette page dans DocCommentXchange.
|Copyright © 2012, iAnywhere Solutions, Inc. - SQL Anywhere 12.0.1|