23 september 2004

Back online again (or why redundancy and failover isn't quite enough)

Some of you might have noticed that this weblog has been off-line for a while. Was it the bogey (Pentium II, 256 MB) webserver that I use to host it? Nope. As a matter of fact, even if I would have had the best hardware or provider in the world, offering 100.0% uptime for a server, it wouldn't have mattered.

Clustering, failover servers, redundant connections and multiple network cards, no difference to my online availability. My domain-name was in transit. It was switching ownership from one provider to another. While alexthissen.nl was in limbo over the weekend, the site was not reachable as there was no IP address registered with the domain name. So, doing a nslookup on the domain name would have returned a message such as “Non-existent domain” or something similar. The best hardware and software can't save you here.

Let this be a lesson to you all: keep careful track of your domain name registration if you value your site's uptime. The site is non-critical to me, but I do apologize for any inconvenience this may have brought.

Comments

# Frans Bouma said:

You should have asked your former ISP to have set the TTL of the DNS record to almost zero. This would have caused almost no downtime for the DNS (probably a day for very slow DNS servers)

donderdag 23 september 2004 11:22
# Alex Thissen said:

Hi Frans,Actually, I should have asked to set the TTL to a very large value. There was a certain timeperiod where there was no DNS entry for the domain. This happened because ISP1 already dropped the name on Friday, whereas ISP2 hadn't put the name into their DNS records until Monday. Then it was still lots of hours before their correct entry (the initial one had a wrong IP address) was propagated to the top level DNS servers. With a large TTL (let's say 4 days) I might have survived the move. If ISP2 had made the entries earlier and correctly straight away, all would have been fine.

donderdag 23 september 2004 16:44
# Frans Bouma said:

whoa, that's a major screwup from the ISP's side... Which one are we talking about, so I can avoid doing business with them :D.

zaterdag 25 september 2004 9:42