On Wednesday 11 March 2009 5:17 pm, you wrote: > You got it. Both servers serve the same site. If one dies the other > takes over for it. To answer your question about database data, use > the same database server from both nodes. That database server could > be yet another failover cluster. > > The most popular way to do failover database (mysql, postgres) with > heartbeat is by using DRBD (distributed replicated block device) which > will sync the underlying volume that stores the mysql data between the > nodes. When the primary dies, the secondary can mount the data, start > the database server and you are back in business. I imagine the same > strategy could be used with sybase on linux. > > For static content, look at rsync or unison. You could optionally use > drbd to replicate your web content between boxes. Or use NFS to share > the web content from another box altogether. And yes, you guessed it, > that NFS server could be yet another cluster :-). > > When you plan your HA setup, you want to eliminate single points of > failure. If you have two web servers in a cluster using a database > server and the database server dies, so much for your HA web servers. > What about your network switch? If it dies, again, your clustered web > servers are no help, you are still down. > > Point is, clustering a set of resources is just one piece of the HA > puzzle, you have to consider ALL the resources that are needed to > serve up your application and find ways to make them fault tolerant. > > On Wed, Mar 11, 2009 at 3:27 PM, Dimitri Yioulos <dyiou...@firstbhph.com> wrote: > > Ben, > > > > I did as you said, turning off apache on both nodes 1 and 2. When I put > > node 1 on standby, HA turned on httpd on node 2. When I brought it out > > of standby, HA turned on httpd on node 1, and turned it off on node 2. > > So, success! Thank you very much! > > > > OK, I think the lightbulb just got switched on. The Web sites on nodes 1 > > and 2 should be exactly alike. If node 1 goes down, then node 2 kicks > > in, delivering the exact same content. Right? Doh! (I'm going to ask > > for my college tuition money back :-) ). > > > > If I might press on, how would that work with a database (take any; we > > use sybase running on Linux here). If the database on the "back up" > > server/node 2 is off, to be powered on if the database on the node 1 is > > unavailable, how is data replicated between the two? I hope it's OK to > > ask this. > > > > Dimitri
Beautiful! Thanks so much for taking the time to do the hand-holding and create the detailed responses. I get it now. It probably won't be the end of my questions, though, but I'll try and make them less lame :-) . Again, thanks! -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. _______________________________________________ Linux-HA mailing list Linux-HA@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha See also: http://linux-ha.org/ReportingProblems
