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I am attempting to formulate a Disaster Recovery strategy for our company website and would like to know if the following is even possible theoretically or practically? If I ask our Domain registrar to set our Domain DNS TTL to 3600 permanently, then host our website on a second server that mirrors the primary server will I theoretically be able to switch from primary to secondary in 1 hour limiting our website downtime. Any advice would be greatly received. |
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That should work fine. Operating systems and browsers may cache DNS lookups, so users may see the downtime as longer. (More info here: http://dyn.com/web-browser-dns-caching-bad-thing/). You could reduce the TTL even further, down to the time it takes your mirror to catch up with changes on your main site. |
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Most providers won't let you permanently set a low TTL because it significantly increases the load on their servers. Others charge more for a more dynamic service. So it is worth checking that they will do it before you count on it. |
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