Setting up a Mirrored Server
4D Version 3.5.4

The time required to set this will depend on the size of the data files, and how fast the hard drives are and the network. Probably the longest time will be running 4D Backup. For a site with two servers with RAID drives, a 100Base-T network, and 5 gigs of data took me about 1.5 hours to setup. Therefore plan your time.

The first thing that needs to happen is that you have a second server computer that has a similiar hard drive volume structure as the main server. It needs to be on the same network, and be the same platform as the main server.

So for example the Mirrored Server has the following Volume Structure. Which is the same on the main server.



On the C Drive of the Mirrored Server there will be a folder called Jonoke. In this folder would be the following Files and folders.



The 4D Backup application needs to be in the its own folder as there are files that it has that have the same name as the server (DLL Files).



1. Install the structure on the Mirrored Server
2. Install the full Server software so that it can run as a server if ever needed.
3. Shut down the main server’s MediFile
4. Copy the data files across to the Mirrored Server and place in a similiar location as the main server
5. Launch 4D Backup
6. Click on the Mirror button.




7. Go to the directory with the structure in it.
8. In the popup at the bottom of the dialog select Compiled Structure



9. Select the MediFile structure.




10. Enter the Admin name and password and click on connect.



11. If this is the first time setting up this structure it will ask you for the 1st segment of the data file. Find it and select it.




12. From the File menu select Preferences.


13. Select delete oldest segment before saving newest and set the Maximum Segment Size. NOTE that this is in Megabytes rather than k like on the server. Therefore 2000 is a good number. Click on the OK button.



14. From the File menu select Save As, and save it with the name Mirror.
*** IT MUST BE SAVE WITH 1st DATA SEGMENT ***

15. The screen will look similar to the next diagram.



In this case when the Mirror server receives the log file it will place it on the D Drive. Since the mirror computer receives the log, we need to ensure there is enough room for it. For this reason the log should be updated at regular intervals so that it does not get too large.

Depending on the site, this could be between every 1-4 hours.

*** Ensure to pick one that has enough room to hold all the segments. ***

17. In the Full Backup Dialog there are some setting you need to make. They are shown in the next diagram.

- Select the Destination Volume for the backup segments.
- Deselect backing up the structure, it is not needed since can easily be obtained from Jonoke via the Internet, or on the last CD.
- Set the Number of Backup sets to 1.
- Don’t turn on verify backup. Since we are just doing this because 4D Backup insists on it we do it. We should have our real backup on tape.
- Click on the ‘Backup’ button to start

18. Though we indicated the volume in the previous dialog we indicated which volume we wanted to backup on, we are asked what to save the file as. Just use the default name BUT select the volume we want to backup to. By default it goes to the volume with the structure on it.

Click on the Save button.

19. As the backup is occuring you will be shown the progress of the backup, as well as the amount of free space on the target volume.

20. As the backup files are created it will ask you what to name each segment, and where to save them. This does permit you to put them on different volumes. This is down through the standard file save dialog.



21. At the end of the backup you will be asked if you want to save the backup parameters. Select OK, and ** Save these with the 1st segment of the data file ***



22. Once the backup is complete, from the File menu select ‘Select Log’. Since one has not been created you will need to create the log. Note that one does not automatically get created or set for you. You can see this as shown in the next diagram.






Once you have created the log, the server will show that you have done this.




23. Ideally the log file will be placed on the mirrored server. If this can’t be done because the drive cannot be mapped, then store the log file on the main server.

24. In the Backup Scheduler select Mirror every checkbox. Set the unit of time, and the number of units. In this example the system is being mirrored every 2 hours.

25. Click in Next Mirror checkbox and enter in the time for the next mirror. For testing purposes I recommend
that you put it within 4 minutes of the current time so you can see it work. For now don’t check off the ‘only if modified box’. Do that once it is set up properly.




26. From the Backup menu select Update Mirror. You will be presented with a dialog similiar to logging onto the server. Select the mirrored server and connect.






From the File Menu select Save as, and save this configuration in the same directory as the 1st data segment. If you don’t save it there 4D Backup will not know which mirror backup server to send the log to.





Ensure to set the Number of sets to none. This means that it will not keep a bunch of old logs.

Operation

As every addition, modification, and deletion of record occurs on the server it writes the same information to the log file. The log file is then sent to the mirror backup server where the same transactions are performed on the mirror backup. The file is optimized to be small, and therefore does not take long to maintain, or send to the mirror server.

The only indication on the main server that the log file is being created is the indication that it has a log file.



When the Main Server sends the log file to the mirrored server it will show this in the Backup Scheduler dialog. The Next Mirror indication will change to mirror in progress. When it is finished it will indicate when the next mirror is due.

Operation on the Mirror Backup

When the 4D Backup on the mirror server receives a log it integrates it into the data file. If you were to watch it when it does this you would see a small dialog showing you its progress. At a site with 5 people working all day on the system it will only take about 3 minutes to integrate a whole day’s log.

When the Main Server Fails

If you have determined that the main server cannot run, you need to perform the following steps.

1. Update the mirror backup with the latest log file.
2. Shut 4D Backup down.
3. Launch 4D Server, and select MediFile.
4. You are now ready to go with the Mirrored Server.

Is the Mirror Occurring

There is one indication if there are problems with the mirror. In the Backup Scheduler in the area where the next mirror time is indicated it will state if there is a problem. Depending on the problem you will need to take different action.

You can set a preference for a larger alert to show if there is a problem.

Typically once a mirror is setup it will work fine.

Sending a Site an Update

When you send a site a MediFile update you need to update structures on both computers. ** Ensure that you have integrated the latest log on the backup before shutting down the main server and the mirror. **

Place the structures on both the Mirror Server and the main server. Launch the Mirror Server 1st. Select the structure. It will do any indexing if needed.

Launch the main server. It will start the indexing. Ensure that the mirror is set up and works. Run a few tests.