Ensure that the arbiter server was started using the:

For example:

dbsrv16 -n mirror_arbiter -su sql -x "TCPIP(PORT=6870;DOBROAD=no)" -xf "c:\arbiter\arbiter.state" -xa "AUTH=abc;DBN=*" -o c:\arbiter\arbiter.conslog

Copy the database that you want to mirror, along with its transaction logs, to one of the existing partner computers.

Connect to the utility database on the existing partner server. For example:

dbisql -c "UID=dba;PWD=sql;DBN=utility_db;SERVER=mirror_server1"

Start the database to be added using the START DATABASE statement with the MIRROR ON and AUTOSTOP OFF clauses. For example:

START DATABASE 'c:\\server1\\second.db' 
AUTOSTOP OFF 
MIRROR ON;

The database starts.

Connect to the database. For example:

dbisql -c UID=DBA;PWD=sql;SERVER=mirror_server1;DBN=second

Create the mirror server definitions (PRIMARY, MIRROR, ARBITER and both PARTNERS) and the authentication string with the SET MIRROR OPTION.

The authentication string for the new mirroring system must match the authentication string specified by the arbiter's -xa option. The hostnames and ports must match those for the existing partner and arbiter servers. The PARTNER mirror server names must match the -n server option for the partner servers. The PRIMARY and MIRROR server names must not match any server names currently in use by the system.

For example:

CREATE MIRROR SERVER second_primary
AS PRIMARY
connection_string='SERVER=second_primary;HOST=localhost:6871,localhost:6872';

CREATE MIRROR SERVER second_mirror
AS MIRROR
connection_string='SERVER=second_mirror;HOST=localhost:6871,localhost:6872';

CREATE MIRROR SERVER mirror_server1
AS PARTNER
connection_string='SERVER=mirror_server1;host=localhost:6871'
state_file='c:\\server1\\server1.state';

CREATE MIRROR SERVER mirror_server2
AS PARTNER
connection_string='SERVER=mirror_server2;host=localhost:6872'
state_file='c:\\server2\\server2.state';

CREATE MIRROR SERVER arbiter_server
AS ARBITER
connection_string='SERVER=mirror_arbiter;HOST=localhost:6870';

SET MIRROR OPTION authentication_string='abc';

Create a backup of the database and copy the back up to the second partner server. For example, use the dbbackup utility.

dbbackup -c "UID=DBA;PWD=sql;SERVER=mirror_server1;DBN=second" "c:\server2"

Connect to the utility database on the second partner server. For example:

dbisql -c "UID=DBA;PWD=sql;SERVER=mirror_server2;DBN=utility_db" 

Start the database on the second partner server using the START DATABASE statement with the AUTOSTOP OFF MIRROR ON clause.

START DATABASE 'c:\\server2\\second.db' 
AUTOSTOP OFF 
MIRROR ON;