I have to perform some upgrades and I want to stage the activity with the support of Meraki, as I don't want to perform it in all my switches at the same time. The point is that these services are running 24 hours and are critical to the business, according to the Meraki dashboard and documentation the downtime is 1 minute while rebooting, but after discussion with Support they have recommended to schedule 1 hour downtime per stack (or more if possible as per their comments). They say that having 4 stacked switches (only 2 uplink) may be risky and sometimes issues can be found.
What is your experience on these cases? It doesn't sound very safe to me.
So according to my conversations with Meraki, if you have multiple switches in an environment, there will be rolling reboots for the next 30-60 minutes as the firmware is installed. This is so all your switches don't reboot at the same time in one environment. This is how I currently do updates in my environment today, although I do make sure I have redundancy to my core systems.
Additionally, there is a beta out right now for staged upgrades for switches: https://documentation.meraki.com/MS/Other_Topics/Staged_Upgrades_for_Meraki_Switches. I personally haven't used that in my environment yet, but I intend to do so.
What happen if your access switches are still downloading the new image and your distribution switches reboot? or the system is intelligent enough not to break the upload process?
I saw the Staged upgrades, but I can't do it by myself, according to Support I have to make them a call and they will be the one activating the functionality and the process.
Specifically for a 4 stack access that I have, with 2 uplinks to the distribution, they said that issues may happens and they are recommending me to schedule at least a 1 hour downtime per stack. That's a lot actually... for a critical business running 24 hours that's not easy to assume.
The system won't break the upload process. If I recall correctly, when you schedule an upgrade, the firmware is downloaded about 5-10 minutes prior to the scheduled time. This is why when you choose to "Upgrade Now" the upgrade happens 5 minutes from when you hit the button, not NOW. After the scheduled time, the reboots can happen during any time in the next 30-60. So if you schedule 4 switches to upgrade firmware at 1am, the first switch may not reboot until 1:10.