Less known Solaris Features: Remote Mirror with AVS - Part 4: Testing the replication.
One of the most essential tasks when configuring disaster recovery mechanism is training the procedure. Thus let´s test the switch into our remote datacenter. We will simulate a failure now. This will show that the data really get´s replicated to a different system ;)
Okay, at first we leave a timestamp in our replicated filesystem, just for testing this feature. I assume, that it´s still mounted on the primary host.
Please keep the timestamp in mind. Now we switch both mirrors into the logging mode. As an alternative you can disconnect the network cable. This will have the same effect. Whenever the network link between the both hosts is unavailable, both volume will be set to the logging mode. As i use virtual servers, i can´t disconnect a network cable, thus can´t do it this way. Okay …
When you look at the status of the replication on
theoden, you will see the logging state again.
gandalf it´s the same.
Okay, now we mount the secondary volume. Please keep in mind, that we don´t mount the volume via network or via a dual ported SAN. It´s a independent storage device on a different system.
Okay, there is a file called
timetest. Let´s look for the data in the file.
The file and it´s content got replicated to the secondary volume instantaniously. Okay, now let´s switch back to primary hosts, but we create another file with a timestamp before doing that.
Okay, we changed the secondary volume by adding this file, thus we have to sync our primary volume. Thus we do an update reverse synchronisation:
This has two consequence. The changes to the secondary volumes are transmitted to the primary volume (as we use the update sync we just transmit this changes) and the replication is started again. Okay, but let´s check for our second timestamp file. We mount our filesystem by using the primary volume.
Et voila, you find two files beginning with
timetest and the second version contains the new timestamp we´ve have written to the filesystem while using the secondary volume on the seondary host. Neat, isn´t it?