7.14.3. Performing Maintenance on an Entire Dataservice

To perform maintenance on all of the machines within a replicator service, a rolling sequence of maintenance must be performed carefully on each machine in a structured way. In brief, the sequence is as follows

  1. Perform maintenance on each of the current slaves

  2. Switch the master to one of the already maintained slaves

  3. Perform maintenance on the old master (now in slave state)

  4. Switch the old master back to be the master again

A more detailed sequence of steps, including the status of each datasource in the dataservice, and the commands to be performed, is shown in the table below. The table assumes a three-node dataservice (one master, two slaves), but the same principles can be applied to any master/slave dataservice:

Step Description Command host1 host2 host3
1 Initial state   Master Slave Slave
2 Set the slave host2 offline trepctl -host host2 offline Master Offline Slave
3 Perform maintenance   Master Offline Slave
4 Validate the host2 server configuration tpm validate Master Offline Slave
5 Set slave host2 online trepctl -host host2 online Master Slave Slave
6 Ensure the slave (host2) has caught up trepctl -host host2 status Master Slave Slave
7 Set the slave host3 offline trepctl -host host3 offline Master Slave Offline
8 Perform maintenance   Master Slave Offline
9 Validate the host3 server configuration tpm validate Master Slave Offline
10 Set the slave host3 online trepctl -host host3 online Master Slave Slave
11 Ensure the slave (host3) has caught up trepctl -host host3 status Master Slave Slave
12 Switch master to host2 See Section 7.12, “Switching Master Hosts” Slave Master Slave
13 Set the slave host1 trepctl -host host1 offline Offline Master Slave
14 Perform maintenance   Offline Master Slave
15 Validate the host1 server configuration tpm validate Offline Master Slave
16 Set the slave host1 online trepctl -host host3 online Slave Master Slave
17 Ensure the slave (host1) has caught up trepctl -host host1 status Master Slave Slave
18 Switch master back to host1 See Section 7.12, “Switching Master Hosts” Master Slave Slave