Defining a Loopback Server

Steps and restrictions for defining a loopback server:
  • Pick, or newly define, a db server alias for the ER ‘pseudo’ server you are going to define, on the same Informix instance that you want to run loopback replication on
  • This server port must also be tcp based (onsoctcp, ontlitcp protocols), and its alias name, in onconfig file, must appear after the name used for the instance's main ER server(DBSERVERNAME & DBSERVERALIASES)
  • The ER loopback (‘pseudo’) server must be defined as a non-root server under the instance’s main ER server
  • Any (root or non-root) server in your ER domain can have at most one loopback pseudo server defined
  • ER loopback server (group) names must be unique in the ER domain, as any other ER node names
  • If ER was not in use before, so no ER domain existed yet, you’d first define the main server, then the loopback server, and the two would form a new ER domain.
Sample command for defining a loopback pseudo server for a pre-existing ER server g_er_server: 
cdr define server --connect=g_er_server g_loopback --init --sync=g_er_server –nonroot
SQLHOSTS file example: 
g_er_server group    -       -      i=1
er_server   onsoctcp *myhost 17001  g=g_er_server
g_loopback  group    -       -      i=2
er_loopback onsoctcp *myhost 17002  g=g_loopback
DBSERVERALIASES example: 
DBSERVERALIASES er_server,er_loopback
where g_er_server is the primary group name for the local server, g_loopback is the pseudo ER group name for the local server.
Parent topic: Loopback Replication