Less known Solaris Features: Point-in-time copy with AVS - Part 9: Disaster recovery
The process of syncing master and shadow is bidirectional. You can´t not only update the shadow from the master, you can update the master from the shadow as well. This is a really neat feature for diaster recovery.
Let´s assume, you tried a new version of your software. At first all is well, but a minute later the system is toast. Later you will find out, that there was a race condition in the new code, that only manifested on your production system. But you don´t know this now. And to add insult to injury, your face go white after looking into the directory.
The new code killed your
testindex-files. Zero bytes. And you hear the angry guy or lady from customer support shouting your name. But you were cautious, you´ve created a point-in-time copy before updating the system.
So, calm down and recover before a customer support lynch mob reach your office with forks and torches. Leave the filesystem and unmount it.
Now sync the master with the slave. Yes, the other way round.
Okay … after a few moments the shell prompt appears again. Now you can mount it again.
Let´s check our work and check the
Phew … rescued … and the lynch mob in front of your office throws the torches out of the window, directly on the car of the CEO (of course by accident ;) )