The standard answer for this is “not at all”. Fix the software to handle restarts in random order. If you really need SOME servers to start first (example: Active Directory) put them on USV’s that are possibly surviving a LOT longer. A low power atom based server is good enough as Active Directory controller and will survive a day on a small USV.
Do high level UPS give other options to fix the restart sequence ?
No. I would say it is generally assumed programmers are competent enough to work around the issue properly.
What you COULD do is:
- Have servers start “randomly”. Except for DHCP / Active Directory there is nothing really demanding an order that can not be fixed.
- Have a control server after some time (5 minutes) start the services on the various machines in the correct order.
I would say that this type of setup is a lot more common. I would call any software that REQUIRES server starts in a particular order (outside of pure infrastructure) as broken and unfit for business.
Just as note: our own setup is a low cost 20kva USV (low cost because we got one used) for the servers, with a slaved 2000VA USV for a machine serving as “root” of the network (and backup machine). Slaved means that the USV is behind the big one – so it only switches to battery when the large one (that lasts between half an hour and 8 hours depending on how much of our computing grid is online) is going into terminal shutdown.