Sybase 12.4.2 User Manual

Determining your data backup and recovery strategy

 

Make a full backup of each database just after you create it, to provide a base 
point, and perform full and incremental backups on a fixed schedule thereafter. 
It is especially important to back up your database after any large number of 
changes. 

Your backup plan depends on:

•

The load on your system

•

The size of your database

•

The number of changes made to the data

•

The relative importance of faster backups and faster recovery

When you decide whether to do a full, incremental, or incremental_since_full 
backup, you need to balance the time it takes to create the backup with the time 
it would take to restore. You also should consider media requirements. A given 
incremental backup is relatively quick and takes a relatively small amount of 
space on tape or disk. Full backups are relatively slow and require a lot of 
space.

Incremental_since_full is somewhere in between. It starts out as equivalent to 
incremental, but as the database changes and the number of backups since a full 
backup increases, incremental_since_full can become as time-consuming and 
media-consuming as a full backup, or worse.

In general, the opposite is true for restore operations. For example, if you need 
to restore from a very old full backup and a dozen or more incrementals, the 
restore may take longer and the backup may use up more space than a new full 
backup. 

The obvious advantage of incremental backups is that it is much faster and 
takes less space to back up only the data that has changed since the last backup, 
or even since the last full backup, than to back up your entire database. The 
disadvantage of relying too heavily on incremental backups is that any eventual 
restore takes longer.