While you've probably heard time and time again how important it is that you run
EZ-Snapshot on a regular basis, you may still be confused as to how it actually works, and what options you have when running the backup. We hope that the following will answer some of your questions.

Choosing the Incremental (complete) Backup Option

We strongly recommend that you run incremental (complete) backups whenever you do a backup. This is because doing so checks many attributes of each file to determine if it has changed and needs to be backed up as a result. Specifically, TSM performs the following when running an incremental (complete) backup:

• Backs up all your new files

• Backs up files whose contents or attributes have changed
• Expires backup versions on the server for files that have been deleted from your workstation by changing the active backup versions into inactive backup version

• Automatically backs up the Windows NT registry if you run incremental backup on the entire system drive

As an example of what we mean by "active" and "inactive" versions of a file, let's say that you create a new file on your workstation, and an Incremental (complete) backup is performed on Tuesday at 11pm. This file is then stored as the active version.

When another Incremental (complete) backup is performed on Thursday, TSM uses that active version to compare the file with your workstation to see if the file has changed since the previous backup. If the file has changed, it is backed up again. The newest backup version from Thursday then becomes the active version, and the file from Tuesday is marked as the inactive version. Just remember: The most recently backed up version of the file is always the active version, as long as it still exists on the workstation and as long as you use the Incremental (complete) backup option.

If you delete a file from the workstation, TSM will detect this the next time an Incremental (complete) backup is performed, and will now list all backed up copies of that file as being inactive. The inactive file remains on the TSM server for 60 days, and is then deleted.

Selecting the Incremental (date only) or Always Backup Options

If you wish, you can select the Incremental (date only) or Always Backup option. Please note, however, that we strongly recommend that you do not choose either of these options, because they:

• Query the server only for the date and time of the last incremental backup, and process only a fraction of the data processed by the Incremental (complete) backup.

• Do not ensure that the files on the server match the exact state of the files on your workstation, because both of these backup options are date-specific. This means that if an existing file's last modified date is listed as being after the last backup was run, the file will still be backed up. However, if you create any new files after the last backup, they will not be backed up
• Do not recognize any files as ever being deleted from your machine, and no version expiration ever takes place. (That is, there are no "active" or "inactive" versions.) As a result, no files are ever removed from the server, and you can quickly run out of storage space.

If you have files with extensions such as .exe, .zip or .MP3 on your PC, these files are already compressed, and will not be compressed further when they are backed up to the TSM server.

Backup & Restore

If you click on either the Backup or Restore option from the main Tivoli Storage Manager window, and then click on the + sign next to File Level, the disk level will display rcsUserID\c, as shown in the window below. If you then click on the + sign next to the disk level, the file list will display. Please note that Disk Level is the only option you can choose to have deleted from the TSM server. You cannot delete individual file list directories.

Reviewing What You Have Backed Up

If you wish to see what you have backed up on the TSM server, click on the Restore option in the main Tivoli Storage Manager window, and then click on the + File Level option. This will display the disk level that was backed up. Next, click on the + sign next to the disk level to display each directory that has been backed up.

Click on a directory name, then click on View from the menu bar and scroll to view the File details. An Information window, similar to the one shown below, will appear, showing you the directory/file's Created date, Modified date, and Accessed date. Most importantly, it also displays the Backup Date, which is the last time that particular directory/file was backed up with TSM.

Keep in mind that if you change computers, there might be older disk levels listed on the TSM server. These old disk levels are included in your usage and you might want to have these deleted from the TSM server. To do this, send electronic mail to
ezsnap-support@rpi.edu and request that the disk level name be deleted.