Migrate from Exasol 7.1 to Exasol 8

This article explains how to migrate an Exasol 7.1 database to Exasol 8.

Because of differences in architecture between the Exasol 7 and Exasol 8 platforms, you cannot update an Exasol 7.1 database directly to Exasol 8. Instead, you must create a full backup of the Exasol 7.1 database (level 0 + level 1) and restore that backup on a new Exasol 8 database.

If your database is running Exasol 7.0, you must update to 7.1 before proceeding. For more information, see Update from Exasol 7.0 to Exasol 7.1.

To prevent a risk of data loss and avoid excessive downtime during the update, read through this section and the Update Considerations section before you start the migration procedure.

Prerequisites

  • The database must be running on the latest Exasol 7.1 version.

  • The database nodes must meet the requirements for an Exasol 8 installation. For more information, see System Requirements.

  • You must have a valid Exasol 8 license.

Exasol 7.1 licenses are not valid in Exasol 8 because of differences in the license format. For more information about how to obtain a valid license for Exasol 8, contact support.

Downtime for migration

The planned downtime for a migration to Exasol 8 begins at the step where you must shut down the Exasol 7.1 database in order to restart it on a different port before creating a level 1 backup (Step 4). The total downtime is mainly determined by how long the backup and restore operations take. A restore usually takes approximately the same amount of time as the backup.

For example, if the level 0 backup takes approximately 5 hours and the level 1 backup takes 30 minutes, the total downtime will be at least 6 hours, based on the following calculation:

Create level 1 backup

 30 minutes

Restore level 0 backup

 5 hours

Restore level 1 backup

 30 minutes
Total 6 hours

When you calculate the total downtime for the migration you should allow time for additional operations, such as stopping and starting the databases, and for reverting to the previous version in case the migration fails. Also consider factors in your system environment that might affect the operation, such as network capacity.

Procedure

The migration procedure consists of the following steps that are carried out in Exasol 7.1 and Exasol 8:

Before you continue, we recommend that you read the Administration Tools section to understand how to use the different administration interfaces in Exasol 8.

Step 1: Deploy a new Exasol 8 database

Create a new Exasol 8 deployment with the same number of active nodes as the existing Exasol 7.1 database. You will make a complete restore of the backup from the existing 7.1 database into this database.

For more details on how to install Exasol 8 as an application, see Install Exasol - step by step.

The Exasol 8 database must have the exact same number of active nodes as the database that was backed up. Otherwise, the migration will fail.

Step 2: Create a level 0 backup of your Exasol 7.1 database

Create a level 0 backup of the Exasol 7.1 database on a remote archive volume. The volume must be reachable from the Exasol 8 database.

For more information about how to start a manual backup in Exasol 7.1, see Manual Backup (this step is identical for all deployment platforms).

The level 0 backup procedure will not require any downtime.

Step 3: Create a remote archive volume in the Exasol 8 database

In the new Exasol 8 database, create a new remote archive volume that points to the source that contains the Exasol 7.1 backup that you created in the previous step.

For information about how to create a remote archive volume in Exasol 8, see Create a remote archive volume.

Step 4: Restart the Exasol 7.1 database on a different port

To ensure that clients are not able to connect to the Exasol 7.1 database during the migration procedure, change the connection port of the database. To do this, you must stop the database, change the connection port, then start the database again.

To minimize downtime, make sure that the new Exasol 8 database is running and reachable before you start the level 1 backup of the Exasol 7.1 database.

The downtime for the migration procedure begins at this point.

  1. Stop the Exasol 7.1 database.

  2. Change the connection port of the Exasol 7.1 database.

  3. Start the Exasol 7.1 database.

Step 5: Backup files in BucketFS

Files in BucketFS are not part of a database backup and must be backed up separately.

Any UDFs and other files that you have stored in BucketFS on the Exasol 7.1 database must be downloaded manually and then uploaded to the Exasol 8 database. To download and upload files in BucketFS we recommend that you use BucketFS Client.

Step 6: Create a level 1 backup of the Exasol 7.1 database

  1. Create a level 1 backup of the Exasol 7.1 database on the remote volume that you used in step 1.

  2. Stop the Exasol 7.1 database.

Step 7: Restore the Exasol 7.1 backup on the Exasol 8 database

For information about how to restore a backup on Exasol 8, see Restore Database from Backup.

Restoring the level 1 backup also restores the level 0 backup. All data from the moment that the level 1 backup started is restored.

The Exasol 8 database will be automatically restarted when the restore operation has completed.

The downtime for migration ends at this point.

The migration is now complete and your Exasol 8 database should be running. Make sure to inform all users about any changes in how to connect to the database, such as modifying the connect string.

Fallback

If the migration is not successful, you can restart the Exasol 7.1 database on the default port.

Next steps

For more information about how to administer your new Exasol 8 database, refer to the relevant topics in the Administrationsection in this documentation.

Support

If you need help with the migration procedure, reach out to our Support team. To get help, create a case.