Administrator's Guide

Preparing to Export or Import Data

Before you export or import data, complete the following tasks:

Use the export or import command with the PREVIEW parameter to verify what data will be moved
Prepare sequential media for exporting and importing data

Using Preview before Exporting or Importing Data

ADSM provides the PREVIEW option on the EXPORT and IMPORT commands. With PREVIEW=YES, the report shows how much data will be transferred without actually moving any data. With PREVIEW=NO, the export or import operation is performed.

Issue each EXPORT or IMPORT command with PREVIEW=YES to determine which objects and how much data will be moved. ADSM sends the following types of messages to the server console and to the activity log for each operation:

Export: Reports the types of objects, number of objects, and number of bytes that would be copied to sequential media volumes. Use this information to determine how many sequential media volumes you need to prepare for an export operation.
Import: Reports the number and types of objects found on the sequential media volumes that meet your import specifications, and reports information about any problems that it detects, such as corrupted data. Use this information to determine which data to move from sequential media volumes to the server and to determine if you have enough storage pool space allocated on the server for the import operation to succeed.

To determine how much space is required to export server definitions and all backup versions, archive copies, and space-managed files to sequential media volumes, enter:

export server filedata=all preview=yes

After you issue this command, the server starts a background process and issues a message similar to the following:

+--------------------------------------------------------------------------------+
|EXPORT SERVER started as Process 4                                              |
+--------------------------------------------------------------------------------+

You can view the preview results on the server console and by querying the activity log.

You can request information about the background process, as described in "Requesting Information about an Export or Import Process". If necessary, you can cancel an export or import process, as described in "Canceling Server Processes".

Planning for Sequential Media Used to Export Data

To export data, you must specify a device class that supports sequential media and identify the volumes that will be used to store the exported data. Use this section to help you select the device classes and prepare sequential media volumes.

Selecting a Device Class

You can query the source and the target servers about device classes to select a device class on each server that supports the same device type. If you cannot find a device class on each server that supports a like device type, then define a new device class for a device type that is available to both servers. See Chapter 8. "Defining Device Classes".

Notes:

If the mount limit for the device class selected is reached when you request an export (that is, if all the drives are busy), ADSM automatically cancels lower priority operations, such as reclamation, to make a mount point available for the export.
You can export data to a storage pool on another server by specifying a device class whose device type is SERVER. For details, see Chapter 4. "Storing Data on Another Server".

Estimating the Number of Removable Media Volumes to Label

To estimate the number of tapes or optical disks needed to store export data, divide the number of bytes to be moved by the estimated capacity of a volume.

For example, cartridge system tape volumes used with 3490 tape devices have an estimated capacity of 360MB. If the preview shows that you need to transfer 720MB of data, then label at least two tape volumes before you export the data.

Using Scratch Media

ADSM allows you to use scratch media to ensure that you have sufficient space on which to store all export data. If you use scratch media, be sure to record their label names and the order in which they were mounted.

Labeling Removable Media Volumes

During an import process, you must specify the order in which volumes will be mounted. This order must match the order in which tapes or optical disks have been mounted during the export process. To ensure that tapes or optical disks are mounted in the correct order, label tapes or optical disks with information that identifies the order in which they are mounted during the import process. For example, label tapes as DSM001, DSM002, DSM003, and so on to indicate the order in which data is stored on the tape volumes.

When you export data, record the date and time for each labeled volume. Store this information in a safe location, because you will need the information when you import the data to the server.

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