Netezza Performance Server Replication Services 3.0.0.0 release notes

The software release number for the first release of Netezza Performance Server Replication Services (NRS) is 3.0.0.0.

Features

Storage
In-built storage is used for queuing replication objects.
VLAN for replication
You can configure a separate VLAN for replication traffic and management during deployment.
Bidirectional replication
Support for bidirectional replication between the replication nodes but for different databases.
Capturing data
Backup and restore functions of Netezza Performance Server are used to capture and apply changes.
Eventual consistency
With Netezza Performance Server Replication Services, one node (the primary) might have newer database content than the other nodes (replicas). The amount of time by which the replica lags behind the primary is called latency, and the amount of data that must be replicated and applied by the replica is the backlog.
Available modes
The replicated database is available only in the Read-Write on one system and the Read-Only mode on the remote systems.

Known issues

Deleting databases from replication error

Under a bidirectional replication set up, you might encounter error when you are running the nzdr delete db command. You can ignore this error.

Running cpds_deploynrs with -i deployment error
You might encounter this message while you are running the cpds_deploynrs script with the -i option.
 mmlsfs: Command failed. Examine previous error messages to determine cause.

You can ignore this error message.

Update and delete database failure on one of the replication systems
If the nzdr update db command failed on one of the replication systems, the nzdr list db output on both systems might differ.

WORKAROUND:

  • Contact IBM Support for assistance.
  • Run the nzdr update db command on the local system again.

    If the nzdr delete db command failed on one of the replication systems, the nzdr list db output still displays the database on the system where it failed to delete the database. You must manually delete the database:

    1. Log in to the system where the nzdr list db output displays the database to be deleted.

      Example:
      ssh e2n1
docker exec -it nrs_replmgmt bash
    2. Remove the database entry from /var/replmgmt/config/global_config.json.
    3. Remove the database from /var/replmgmt/status/status.json.
    4. Prune all Kafka records from the database topic:
      1. Find the database topic name.
        /opt/kafka/bin/kafka-topics.sh --list --bootstrap-server localhost:29092
      2. On the list, find the topic that contains that database name.
      3. Change directories.
        cd /var/replmgmt/kafka/
      4. Modify the prune.config file by adding the topic name and setting offset to -1.
      5. Run the command.
        /opt/kafka/bin/kafka-delete-records.sh --bootstrap-server localhost:29092 --offset-json-file prune.config --command-config /var/replmgmt/config/kafka-client-ssl.properties
        • If the system is primary, log in to the host container and delete the database directory under /nrsbackup/temp_backup_dir.
        • If the system is replica, log in to the host container and delete the database directory under /nrsbackup/temp_restore_dir.

Limitations

  1. NRS does not replicate table objects that are specified with BACKUP DATA OFF and BACKUP OFF. For more information, see ../bnr_improvement/bnr_avoiding_tables.html.
  2. NRS does not replicate the following data objects:
    1. GLOBALS, including user entries and so on.
    2. TEMP TABLE, excluding GLOBAL TEMP TABLE.
    3. Systems with Netezza Performance Server deployed on connector nodes are not supported.
    4. Only two replication nodes are supported.