need advice on sync between computers

Ahoy there,
i have a computer at work running debian that acts as a server and more.
we have a backup computer too. Now, its really bad for our server to go down for more than an hour or so, so i was wondering...
is there a way to set up the back-up computer to have a copy of all the info on the main box (mysql database, server-stuff, etc...)
i could even write something maybe in python (the only one i am comfortable with right now) to keep them going.
is there a way, since both are on the same network, for one box to know if the other has dropped off line so it can take over as the server (means changing its internal ip address so it can get past the router, etc.)

any advice or apps out there that you know of for this kind of thing would really be a pointer for me, i am kinda new at this.

thanks

You run into way more problems than syncing problems with something like this. First is the ARP cache that exists on the router. This means that for at least 30 minutes (maybe longer, depending on the router config), the router will still believe 192.168.0.2 is still at hardware address be:ad:00:00:00:00 or whatever.

I would suggest to do this the right way. If you have access to the server space, get yourself a RedHill WebMux or Cisco CSS, and set up load balancing between the two servers. Then have a machine for the database on the backend that isn't connected to the external network. This will allow you to have real failover between the machines, with the DB server being the only single point of failure.

If you choose to continue down the cheap path, it will bring you to a lot of technical problems. The problems can be overcome, but they get progressively more difficult as it gets bigger.

Best,

Samuel

Quote:

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Originally Posted by wassy121

The problems can be overcome, but they get progressively more difficult as it gets bigger.
Samuel

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Well this is the last thing i need. Because once we go live with this it is going to get big really fast. The database is going to be getting about 3 - 15 thousand updates per day.
i will look into your tip. Wasted time is wasted money.

thanks

What is the server limit for those?

Sometimes we get mission critical customers asking for fail over solutions.

Also what's good price topay on say ebay for used one?