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
Perform maintenance on each of the current Replicas
Switch the Primary to one of the already maintained Replicas
Perform maintenance on the old Primary (now in Replica state)
Switch the old Primary back to be the Primary 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 Primary, two Replicas), but the same principles can be applied to any Primary/Replica dataservice:
| Step | Description | Command | host1 | host2 | host3 |
|---|---|---|---|---|---|
| 1 | Initial state | Primary | Replica | Replica | |
| 2 |
Set the Replica host2
offline
| trepctl -host host2 offline | Primary | Offline | Replica |
| 3 | Perform maintenance | Primary | Offline | Replica | |
| 4 |
Validate the host2 server
configuration
| tpm validate | Primary | Offline | Replica |
| 5 |
Set Replica host2 online
| trepctl -host host2 online | Primary | Replica | Replica |
| 6 |
Ensure the Replica (host2)
has caught up
| trepctl -host host2 status | Primary | Replica | Replica |
| 7 |
Set the Replica host3
offline
| trepctl -host host3 offline | Primary | Replica | Offline |
| 8 | Perform maintenance | Primary | Replica | Offline | |
| 9 |
Validate the host3 server
configuration
| tpm validate | Primary | Replica | Offline |
| 10 |
Set the Replica host3 online
| trepctl -host host3 online | Primary | Replica | Replica |
| 11 |
Ensure the Replica (host3)
has caught up
| trepctl -host host3 status | Primary | Replica | Replica |
| 12 |
Switch Primary to host2
| See Section 7.11, “Switching Primary Hosts” | Replica | Primary | Replica |
| 13 |
Set the Replica host1
| trepctl -host host1 offline | Offline | Primary | Replica |
| 14 | Perform maintenance | Offline | Primary | Replica | |
| 15 |
Validate the host1 server
configuration
| tpm validate | Offline | Primary | Replica |
| 16 |
Set the Replica host1 online
| trepctl -host host3 online | Replica | Primary | Replica |
| 17 |
Ensure the Replica (host1)
has caught up
| trepctl -host host1 status | Primary | Replica | Replica |
| 18 |
Switch Primary back to
host1
| See Section 7.11, “Switching Primary Hosts” | Primary | Replica | Replica |