Hello, I'm new here, so sorry if I've choosen wrong forum section.

I have a problem, that i'd like to address to you. We are creating an webapp that shows infos and statistics. And we have a problem about how to 'do right' our server configuration

The thing is that our apps use crons to do few things, and crons sometimes blocks our database, and when that happens, whole application is frozen, which means no user input, no pages loading etc.

What should we do to prevent this from happening? is there a way to mirror the database and hold two of them one for backend and one for frontend, or we should limit connections to the database, or maybe we should use some other method.

Any help would be appreciated

Not much we can tell you, since you give us no details. You don't tell us what version/distro of Linux, what database you're using, what the cron jobs do, when they do it, what applications are running, how many users, what kind of hardware, what storage device(s) hold the database, etc. We can't guess.

Depending on the database and what you're using for backups, there are ways to do a 'hot' backup of a database (that is, back it up while it's running). MySQL has the mysqldump utility, that will take a copy of a database, and shove it into a file. You can restore it from that file later, and you don't have to take the DB down to do it.

Provide some details, and we can try to help.