I have the need to reboot my ASA5520. We have a Active/Standby pair and I want to make sure that they come up playing nicely and not in a tug of war.
Any advice on the proper way to reload these machines and optimize uptime??
If you are not bothered as to which one becomes primary then simply pick one, reload, wait until it has come up and then reload the other one.
As long as you have failover correctly configured there should be minimal downtime, just the time it takes to fail over when you reload.
If you want the primary to stay as the primary then you need to reload this one first, let it come up as standby, then reload the other one and the former primary will now become the primary again.
Note that reloading the standby first is the best approach simply because you only then have one failover ie. when the standby comes backup and resumes it's standby funtionality and then you reload the primary there will be a failover.