OpenText Analytics Database 26.2.x – Replacing nodes

Admin: Replacing a host using the same name and IP address

Mon, 01 Jan 0001 00:00:00 +0000

If a host of an existing database is removed you can replace it while the database is running.

Note

Remember a host in OpenText™ Analytics Database consists of the hardware and operating system on which the database software resides, as well as the same network configurations.

You can replace the host with a new host that has the following same characteristics as the old host:

Name
IP address
Operating system
The OS administrator user
Directory location

Replacing the host while your database is running prevents system downtime. Before replacing a host, backup your database. See Backing up and restoring the database for more information.

Replace a host using the same characteristics as follows:

Run install_vertica from a functioning host using the --rpm or --deb parameter:
```
$ /opt/vertica/sbin/install_vertica --rpm rpm_package
```
For more information see Install Vertica using the command line.
Use Administration Tools from an existing node to restart the new host. See Restart the database on a node.

The node automatically joins the database and recovers its data by querying the other nodes in the database. It then transitions to an UP state.

Admin: Replacing a failed node using a node with a different IP address

Mon, 01 Jan 0001 00:00:00 +0000

Replacing a failed node with a host system that has a different IP address from the original consists of the following steps:

Back up the database.

It is recommended that you back up the database before you perform this significant operation because it entails creating new projections, deleting old projections, and reloading data.
Add the new host to the cluster. See Adding hosts to a cluster.
If OpenText™ Analytics Database is still running in the node being replaced, then use the Administration Tools to Stop Vertica on Host on the host being replaced.
Use the Administration Tools to replace the original host with the new host. If you are using more than one database, replace the original host in all the databases in which it is used. See Replacing Hosts.
Use the procedure in Distributing Configuration Files to the New Host to transfer metadata to the new host.
Remove the host from the cluster.
Use the Administration Tools to restart the database on the host. On the Main Menu, select Restart Vertica on Host, and click OK. See Starting the database for more information.

Once you have completed this process, the replacement node automatically recovers the data that was stored in the original node by querying other nodes within the database.

Admin: Replacing a functioning node using a different name and IP address

Mon, 01 Jan 0001 00:00:00 +0000

Replacing a node with a host system that has a different IP address and host name from the original consists of the following general steps:

Back up the database.

It is recommended that you back up the database before you perform this significant operation because it entails creating new projections, deleting old projections, and reloading data.
Add the replacement hosts to the cluster.

At this point, both the original host that you want to remove and the new replacement host are members of the cluster.
Use the Administration Tools to Stop Vertica on Host on the host being replaced.
Use the Administration Tools to replace the original host with the new host. If you are using more than one database, replace the original host in all the databases in which it is used. See Replacing Hosts.
Remove the host from the cluster.
Restart OpenText™ Analytics Database on the host.

Once you have completed this process, the replacement node automatically recovers the data that was stored in the original node by querying the other nodes within the database. It then transitions to an UP state.

Note

If you do not remove the original host from the cluster and you attempt to restart the database, the host is not invited to join the database because its node address does not match the new address stored in the database catalog. Therefore, it remains in the INITIALIZING state.

Admin: Using the administration tools to replace nodes

Mon, 01 Jan 0001 00:00:00 +0000

If you are replacing a node with a host that uses a different name and IP address, use the Administration Tools to replace the original host with the new host. Alternatively, you can use the Management Console to replace a node.

Replace the original host with a new host using the administration tools

To replace the original host with a new host using the Administration Tools:

Back up the database. See Backing up and restoring the database.
From a node that is up, and is not going to be replaced, open the Administration tools.
On the Main Menu, select View Database Cluster State to verify that the database is running. If it’s not running, use the Start Database command on the Main Menu to restart it.
On the Main Menu, select Advanced Menu.
In the Advanced Menu, select Stop Vertica on Host.
Select the host you want to replace, and then click OK to stop the node.
When prompted if you want to stop the host, select Yes.
In the Advanced Menu, select Cluster Management, and then click OK.
In the Cluster Management menu, select Replace Host, and then click OK.
Select the database that contains the host you want to replace, and then click OK.

A list of all the hosts that are currently being used displays.
Select the host you want to replace, and then click OK.
Select the host you want to use as the replacement, and then click OK.
When prompted, enter the password for the database, and then click OK.
When prompted, click Yes to confirm that you want to replace the host.
When prompted that the host was successfully replaced, click OK.
In the Main Menu, select View Database Cluster State to verify that all the hosts are running. You might need to start OpenText™ Analytics Database on the host you just replaced. Use Restart Vertica on Host.

The node enters a RECOVERING state.

Caution

If you are using a K-Safe database, keep in mind that the recovering node counts as one node down even though it might not yet contain a complete copy of the data. This means that if you have a database in which K safety=1, the current fault tolerance for your database is at a critical level. If you lose one more node, the database shuts down. Be sure that you do not stop any other nodes.