Backup

[Cojast]

Is there a way to do a Mirror of one server to another over the network. I have two of the same boxes (hardware and software) i have Fedora 3 Server on both. I want to be able to mirror one of the servers to the other over the network so if one server breaks i just need to change the IP address of the other and that will pick it up. I am mirror a web server if that helps any.


Thanks

MDK3

 

[zeland]

I suppose you could the way of rsync+hearbeat combo.


--== Anything can go wrong. It's just a matter of how far wrong it will go till people think its right. ==--

 

[TrojanWarBlade]

What about using external network based storage for the stuff that changes regularly? Then both machines will see the same data.
Or you could run raid mirroring on both machines and just swapr drives over when you want to switch machines.


Trojan.

 

[Cojast]

raid mirroring wont work cause what if the main machine burned up then the harddrive would go to and i would be able to switch... besides the machine are at different locations.

 

[lgarner]

I'd second the rsync+heartbeat method. I'd rather have the failover be automatic and fairly fast than have to do it manually.

Also look at cfengine for managing configuration files and software installations. Remember that you can't truly mirror the complete servers since that would mirror the network setup and foul up your connectivity. Just set up two servers as identically as possible and mirror the application configuration files, data and software.

 

[Cojast]

Lgarner
that is exactly what i want to do. I want to be able to change the IP address on the second server incase something happens to the first, that way the websites will only be down for a few minutes at most.

Thanks alot

 

[lgarner]

Oops- I just noticed that you say that "the machines are at different locations". Usually that means that they are not on the same network, so simply switching IP addresses won't work.

You could look into a load-balancing solution, like F5, Cisco or even Linux Virtual Server. If you're worried about one location being offline, then I think a DNS-based solution is what you'll need. F5 has something for that, I think, as do some others. Try searching for "dns failover".

As for my (and zeland's) suggestion, which will work if the servers are on the same subnet, check out linux-ha.org. Basic server-is-down type failover is pretty easy to set up. You can also get more complex, like failing when the httpd service isn't running or responding.

 

[Cojast]

Actually the servers are on the same subnet. They are just different buildings. I miss spoke. But i will diffently check that site out and thanks again for the help.


Cojast

 

[ericbrunson]

You can set up raid 0 with your local volume and a network block device so your changes are replicated to the remote server in near real time. Heartbeat and ip-takeover would then handle one server failing, or even use a load-balancing architecture while they're both up.

See ndb.sf.net for more info on the network block device. It have been part of the kernel since version 2.1.

 

[Cojast]

thanks but the link takes me to a nutrient website

 

[ericbrunson]

Sorry, typo. It's

http://nbd.sf.net