http://linuxexchange.org/questions/768/best-practices-for-geo-redundancy<p>We have a Lighttpd/Perl/MySQL web service we run on an Ubuntu VPS, and want to add redundacy so that if our datacenter has issues, we stay up.</p> <p>Interested in thoughts and comments on our proposed solution:</p> <ul> <li><p>We're looking at using GlusterFS to mirror the web roots and config files for our apps, and MySQL Replication in multimaster mode to mirror the database. Both would run over the WAN/Public Internet between the two datacenters with IPSec Transport mode encryption.</p></li> <li><p>We'd use dual A records (an IP at each datacenter) to host the sites. This would provide for round-robin while things were working, and would failover within 4 seconds (worst case, most browsers release a DNS pinning in 1000ms) to the other server, should connectivity be lost.</p></li> <li><p>GlusterFS and MySQL replication would both "self heal" and update the other server automatically once connectivity was restored, so there is no issue of needing to update an out-of-sync server after failover, and both servers can run in "live mode" with both A records live all the time - so there is no DNS propagation to take place to make a failover happen.</p></li> <li><p>In the event of software failure or a need to take one server offline for maintenance (rather than connectivity failure) we could simply pull one server's IP offline using the VPS control panel, or firewall it temporarily with iptables on the server itself.</p></li> <li><p>As well as the automatic failover we'd experience with a datacenter outage, we could also automatically initiate a failover in the event of software failure on one server using automatic monitoring - if one server isn't returning the content we expect to see, we would get an alert, and the monitoring software would automatically pull the offending server offline using the VPS host's API - causing requests to fail over to the other.</p></li> </ul> <p>Interested to know if anyone has tried doing anything similar, or for any thoughts, comments or suggestions on the above strategy.</p>enWed, 20 Apr 2011 14:10:28 -0400http://linuxexchange.org/questions/768/best-practices-for-geo-redundancy#2451<p>Please accept an answer so the question/answer can be finished. Or provide more details so we can help.</p>rfelsburgWed, 20 Apr 2011 14:10:28 -0400http://linuxexchange.org/questions/768/best-practices-for-geo-redundancy#2451