Database Backup

Zim Backup Server can back up database in real-time, on-line mode, like this example.

If you have two Zim databases being serviced by Zim Server and described in zimdb.zim as:

1;MyBase;c:\zim8databases\test8\mybase
2;Example;c:\other\example

These databases are located in c: and Zim Server is NOT running yet.

The zimconfig.srv server configuration file contains the following:

Backup path u:\backup
Audit path u:\audits
...

Notice that the directories u:\backup and u:\audit are pointing to the networked drive u:, probably in another computer somewhere in the network. The backup path entry tells Zim Server that the committed transactional files must be placed in the u:\backup directory, whereas the entry audit path tells where the current transactional file must be placed in u:\audit.     

Let us consider that we are going to back up these two database in the drive u: as well, in the following addresses:

database MyBase is going to be backed up in u:\mybase

database Example is going to be backed up in u:\example

Now, follow these steps:

1) Physically copy the two database, from their original places, to the back up places. Remember that you can have areas.zim files in these databases; therefore, you must adjust these files in the backed up places;

2) Create a zimbk.zim file with the following entries:

1;MyBase;u:\mybase
2;Example;u:\example

3) Start Zim Server in drive c:;

4) Start Zim Backup Server in drive u:;

As soon as users start performing updates with the assistance of Zim Server, these updates will be also applied to the databases managed by Zim Backup.

Notice that all references to database locations were in terms of network drives. This means that these drives can be located anywhere in the network. In this way, Zim Server and Zim Backup can be running in the same machine or in different machines. As well, audit and backup files can be placed in the same or in different machines.

However, it is recommended that the original databases should be place in one computer, the audit and backup paths in another computer and the backed up database possibly in a third one for reasons of safety.

Note: The zimbk.zim on the second computer MUST have the same number of entries as the zimdb.zim file on the first Computer for the backup to work properly.

Backing Up Database Files

A database can be backed up to take or to another disk using one of the following possibilities:

1) If there is a real-time back up in place using Zim Backup Server, stop Zim Backup and then copy all files from the database to the desired media. These files are those belonging to the Zim database, like ZIMxxxx files and audit and backup transactional files. While the copy process is in progress, Zim Backup will not perform backup activities, but Zim Server is still running and normally servicing users. When the copy finished, Zim Backup can be started again and the database will automatically get all modifications since when it was stopped;

2) If Zim Backup is not running, then Zim Server has to stopped and the corresponding files must be copied to the desired media. While the copy process is in progress, Zim Server cannot be started as it possesses all files and will not allow file operations over its files.

Restoring Databases

If, for some reason, the main database becomes unavailable, then the administrator can take one of these two actions:

1) If Zim Backup Server is running, just stop it and start Zim Server in its place. Therefore, the database that was being backed up will now serve as the main database. This process doesn't take longer than two or three minutes to be accomplished. Users can start their sessions normally again;

2) If Zim Backup is not running, a database has to be brought from a previous backup from tape or from disk. This can take several hours depending the size of the database and the media where the copy was stored.