Altering multiplex servers

You can perform various operations to alter servers from the server property sheet in Sybase Central or using Interactive SQL. The coordinator must be running. Although you can run the ALTER MULTIPLEX SERVER command from any server in the multiplex, it is recommended that, like all DDL, commands be run on the coordinator.In all cases except when altering role from reader to writer, the named server is automatically shut down once the change is committed.

1. Open the server property sheet.

2. Change the server name on the Configuration tab.

1. Open the server’s property sheet.

2. On the Configuration tab, change the database file path.

1. Start the server, connect to it, and issue a command in the following format:

2. ALTER MULTIPLEX SERVER server name DATABASE 'new db file path'
   

3. This command also shuts down the named server.

1. Open the server property sheet.

2. On the General tab, change the server role (reader/writer).

1. Start the server, connect to it, and issue a command in the following format:

2. ALTER MULTIPLEX SERVER server name ROLE {WRITER|READER}
   

   You cannot change the role of coordinator. Changing a write server to a reader automatically shuts down the server.

1. Open the server’s property sheet.

2. On the Configuration tab, change the host/port information.

1. Start the server, connect to it, and issue a command in the following format:

2. ALTER MULTIPLEX SERVER server name HOST 'hostname' PORT portnumber
   

   This command also shuts down the named server.

If a multiplex secondary server will be shut down for an extended period of time, that server should be excluded. Excluding the server allows the coordinator to ignore this server when performing version cleanup. Otherwise, the coordinator will need to reserve all old versions of IQ objects since the secondary node was shut down. This takes up unnecessary disk space. A designated failover server cannot be excluded unless it is the last secondary node to be excluded in the multiplex. Include/exclude does not apply to the coordinator.

1. Open the server property sheet.

2. On the General tab, include or exclude the server.

An alternate method is to right-click the server and select context menu Control > Include/Exclude.

1. Start the server, connect to it, and issue a command in the following format:

2. ALTER MULTIPLEX SERVER server name STATUS {INCLUDED|EXCLUDED}
   

3. If the target server is running, it is strongly recommended that you shut it down before excluding it. In case you do not, it will eventually shut itself down, but it is better that you plan for and shut it down prior to excluding it. Excluding a server shuts it down. After including a server, the server must be synchronized and then started.

1. Right-click the Multiplex Name in the Sybase Central tree view.

2. Choose Designate Failover.