PRIMARY ACTIVE

The servers are connected, and this server (the primary server) is accepting read/write transactions and sending the data to the secondary server. The secondary server must be in SECONDARY ACTIVE state.

PRIMARY ALONE

The peer servers are not interconnected. The peer might be up, but it is not connected and therefore is not accepting any transactions. The peer might be in the SECONDARY ALONE state).

This server (the primary server) is actively accepting and executing read/write transactions and collecting them to be sent to the secondary server later.

PRIMARY UNCERTAIN

The servers have disconnected abnormally and the AutoPrimaryAlone configuration parameter is set to No. In the PRIMARY UNCERTAIN state, any unacknowledged transactions remain in a pending status, which means that this server (the primary server) does not commit or roll back the transaction until the server is changed to another state.

The operator has three possible actions:

If you want the primary server to automatically switch to PRIMARY ALONE rather than PRIMARY UNCERTAIN when it loses contact with the secondary server, then set the AutoPrimaryAlone configuration parameter to yes, see AutoPrimaryAlone.

The High Availability Controller (HAC) can maximize safety by always switching the server from PRIMARY UNCERTAIN to SECONDARY ALONE. This prevents the possibility of dual primaries. However, it also prevents users from updating data on the server. For more information, see Network partitions and dual primary servers.

SECONDARY ACTIVE

The peer servers are interconnected, and this server (the secondary server) is accepting incoming transaction log data from the primary server. The transactions are executed on the secondary server so that it has the same data as the primary server. The transactions are also written to the transaction log of the secondary server so that the secondary server can recover the data if the secondary server fails.

Additionally, clients can perform read-only transactions on a server in the SECONDARY ACTIVE state. When a server is in the SECONDARY ACTIVE state, its peer must be in PRIMARY ACTIVE state.

SECONDARY ALONE

This server (the secondary server) is disconnected from its peer server. Only read requests are accepted. The server can be connected to the peer by running ADMIN COMMAND 'hotstandby connect' on either the primary or secondary server.

STANDALONE

The server has no HSB state (PRIMARY or SECONDARY) and operates in the way a regular stand-alone server operates. Transaction logs are processed and removed in the normal way, too; they are not saved for the secondary server. To resume HSB operation, the server must be set to either PRIMARY ALONE or SECONDARY ALONE, and the primary server has to do a netcopy or copy operation to send a complete copy of the database to the secondary server.

OFFLINE

The server was started in "netcopy listen mode" (also called "backupserver mode"). In this mode, the server is waiting for an incoming netcopy from a server that is in PRIMARY ALONE state. When the server successfully completes netcopy, the server moves to the state SECONDARY ALONE.

You cannot directly observe the OFFLINE state because a server in OFFLINE state does not accept client connections. If you attempt to connect to a server in the OFFLINE state, the following error code is returned:

A server in the OFFLINE state responds only to a netcopy operation.