3. Memory-efficient backup

TSM deals with data one partition at a time, comparing a list at the client end with what is already stored on the HFS, and backing up the difference. In cases where a partition has several million files, this can lead to poor performance, since the lists that TSM is comparing are very long.

The following instructions show how to change the way in which TSM processes your data. One of the two options given in this section will often fix problems related to failing backups if the issue is caused by a high file count.

3.1. Changing the memory-efficient backup option using the graphical user interface

To change the memory-efficient backup option in the graphical user interface, do as follows:
  1. Run TSM: in Windows, run TSM from [Start] > [All Programs] > [Tivoli Storage Manager] > [Backup-Archive GUI]; on a Mac, run TSM from [Applications] > [TSM Tools for Administrators] > [Tivoli Storage Manager]; in Linux, run dsmj as root. The following window will appear.

    Figure 1.
  2. Click on Edit, then Client Preferences. The Preferences Editor window will appear, on the General Preferences section:

    Figure 2.
  3. From the list of tabs on the left, click on Performance Tuning. The options for Performance Tuning Preferences will appear:

    Figure 3.
  4. Under Memory Usage Algorithm to be used during backup, the default Use memory-resident method should already be selected. To have TSM deal with your data one folder at a time rather than a whole partition at a time, change this to Use memory saving method.

  5. If you have already tried Use memory saving method and still find that TSM is running slowly, then you can instead select the third option, Use disk cache method. Please note, however, that this method creates a database on your hard disk, and you will need to have sufficient free space for this database. IBM advise that if your machine is running Windows, you may need 5GB spare for each one million files that you have; if you have a Mac, then 800MB is needed for each one million files; and on Linux 200MB is needed for each one million files.

  6. Now click OK in the Performance Tuning Preferences window. This will take you back to the main TSM window.

  7. If you wish, you can now try running a manual backup to see if TSM performance is improved. Note that TSM will run slower if you are working on your computer whilst you are backing up. For how to run a manual backup, please see our instructions for doing so on Windows, Mac, Linux or Solaris.

  8. Lastly, if you use the automatic scheduled backups, you must now restart the TSM scheduler after making changes to your TSM configuration. If you do not do this then the change that you have made will not be honoured on the scheduled backups. Please see our instructions for restarting the scheduler for Windows, Mac, Linux and Solaris. Alternatively, restarting your machine will have the same effect as restarting the TSM scheduler.

3.2. Changing the memory-efficient backup option by editing the TSM configuration file

To change the memory-efficient backup option by editing the TSM configuration file, do as follows:

  1. Locate the TSM configuration file dsm.opt. The location of this file is platform-specific and can be looked up in our list of TSM Options Files.

  2. In Windows Vista, 7, 2008 and 2008R2, permissions to edit the contents of C:\Program Files are limited. We therefore recommend that you move dsm.opt to the desktop before you open it for editing. Users of these versions of Windows should therefore browse to C:\Program Files\tivoli\tsm\baclient and drag dsm.opt to their desktop. (An alternative is to run your text editor as administrator before using it to open dsm.opt.)

  3. Now add to the end of dsm.opt:

    memoryefficientbackup yes

  4. If you have already tried memoryefficientbackup yes and still find that TSM is running slowly, then you can instead try the following:

    memoryefficientbackup diskcachemethod
    Please note, however, that this method creates a database on your hard disk, and you will need to have sufficient free space for this database. IBM advise that if your machine is running Windows, you may need 5GB spare for each one million files that you have; if you have a Mac, then 800MB is needed for each one million files; and on Linux 200MB is needed for each one million files.

  5. Save the TSM configuration file. If you moved it from C:\Program Files to your desktop in order to edit it, now move it back.

  6. If you wish, you can now try running a manual backup to see if TSM performance is improved. Note that TSM will run slower if you are working on your computer whilst you are backing up. For how to run a manual backup, please see our instructions for doing so on Windows, Mac, Linux or Solaris.

  7. Lastly, if you use the automatic scheduled backups, you must now restart the TSM scheduler after making changes to the exclude rules. If you do not do this then the change(s) that you have made will not be honoured on the scheduled backups. Please see our instructions for restarting the scheduler for Windows, Mac, Linux and Solaris. Alternatively, restarting your machine will have the same effect as restarting the TSM scheduler.

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