Backing-up and Restoring Data
This chapter discusses backup and restore of Mimer SQL databanks. Two types of backup procedures are described:
- System Backup, i.e. backing up the databank files from the host operating system. When using host operating system tools for doing databank file backup, the database server must be stopped in order to keep the database consistent.
- Online Backup, i.e. using the SQL system management statements. The main advantage of online backup is that the database server can continue to operate (backup operations are performed in the background).
Some of the discussion in this chapter refers to shadowing databases, see Mimer SQL Shadowing, which is an optional Mimer SQL module that allows one or more copies of a databank to exist on different disks. Shadowing provides a high level of protection from disk failure because the system will automatically use a databank shadow if the master databank is lost, thus allowing normal database activity to continue without interruption. Databank shadows also allow a copy of a databank to be temporarily set offline (e.g. to be backed-up) without interrupting normal system use.
Several references to transaction handling are made in this chapter. If you are not familiar with transaction handling in Mimer SQL see the Mimer SQL Programmer's Manual, Transaction Handling and Database Security.
A Mimer SQL database consists of a collection of databanks (each in a separate operating system file) containing tables with data used by the applications. The SYSDB system databank contains a data dictionary describing the different objects in the database.
Note: Backup protection for SYSDB is particularly important for protecting the database, since SYSDB contains all information describing the database structure. If SYSDB is lost, the system must be rebuilt from scratch.
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