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Replication and Binary Logging Options and Variables

The next fewsections contain information about mysąldoptions and server variables that are used in

replication and for controlling the binary log. Options and variables for use on replication masters and

replication slaves are covered separately, as are options and variables relating to binary logging. A set

of quick-reference tables providing basie information about these options and

variables is also included

(in the next section following this one).

Of particular importance isthe —server-id [1991] option.

This option is common to both master and slave replication servers, and is used in replication to

enable master and slave sen/ers to identify themselves uniquely. For additional information, see

Section 16.1.4.2, “Replication Master Options and Variables", and Section 16.1.4.3, "Replication Slave Options and Variables".

On the master and each slave, you musł use the —server-id [1991] option to establish a unique

replication ID in the rangę from 1 to 232- 1. “Unique", means that each ID must be different from every

other ID in use by any other replication master or slave. Example: server-id=3.

If you omit —server-id [1991], the default ID is 0, in which case a master refuses connections from

all slaves, and a slave refuses to connect to a master. For morę information, see Section 16.1.1.2,

“Setting the Replication Slave Configuration".

server__uuid[1992]

Beginning with MySOL 5.6, the server generates a true UUID in addition to the server-id [1991]

supplied by the user. This is available as the global, read-only variable

server_uuid[1992].