Backup servers

mike_watts

Member
Recently a hosting company we use went down for a whole day taking all the sites we host with them down too.

Two of our sites need to be up 100%.

I'm thinking of renting two servers with two different companies and having the same site on both so if one goes down the other will be there as a backup, can anybody recommend the best way to do this, do you use two separate nameservers in the domain name setup?

I also looked into hosting companies that offer 100% uptime guarantees, does anybody have experience of these companies - I'm a bit wary of empty promises.

Thanks in advance
 
In theory you could do this by setting the primary name server with host1 and secondary nameserver with host2 but there are many issues with this.

1. The nameservers are selected randomly so you do not know which one a person will land on.
2. The nameserver *should* notice that the site does not resolve and fallover to another nameserver, but this is not always the case. So there might be times hat it does not actually work.
3. As mentioned in #1 the nameservers are random. If you have any type of functionality on yoru website I would not even bother trying as website 1 would need to sync with website 2 and that requires extra work. If you really did want to do it, do it with static sites only.

The other solution might be to handle your DNS yourself through your registrar (such as 123-reg) and modify your A record to point to a different IP if the site goes down. DNS take approx 24 hours to propagate, where A records is minutes or anything up to a possibe hour.

It might even be possible to update the A record (and MX if using email) via a script on another server (possibly a cron job) that checks periodically to see if your site is alive. However, you would need to run this on both webservers (or a third server altogether) and I am not entirely sure you could modify the record remotely through any registrar unless you owned the DNS box yourself.
 
Hi Darren

Thanks for that info about the random selection of nameservers, I didnt realise that. And also for the link, this will be something I'll look into to add to my options, actually I only have one other option and that is to try a different server provider offering 100% uptime, I saw this amongst others: Dedicated Server 100% SLA - ICUK
But you never know untill something goes wrong whether they are true to their word.

I thought 99.9% uptime was okay but when you actually calculate that, it could be that the server is down for 45 minutes every month!

Cheers again, I'll let you know how I get on.
 
I would never trust anyone that claims 100% uptime, pure lie.

The server will need updating from time to time so you have to allow for some downtime thats why any good host will advertise 99.9%.

That doesn't mean that your server will be down for 45mins a month, most months it wont be down at all, others it will be down for a few mins while they switch servers to the latest patched versions add better features when they become available, or move you to a more powerful machine. This also tends to happen in very offpeak times with the good ones, the one I use do thier small manitance at around midnight and it tends to be down for a min or 2 and that is rare when you do.

If the server is shared, someone could also attack one of those other sites on your server and thus bring your site down as a result. Then it's down to how quickly they can get it fixed or get a backup up running and shut down the problem site.

I use UK Web Hosting Company | UKHost4u for my image server, and currently my main server, never had any problems with them, every time I have had a problem, be it a question they have always responded extremely quickly and help is available to 11pm I think with a very quick human response.

When I was first learning I coded unsecurly and as a result someone crashed my server due to my imcompatence, and took every one elses site offline as a result. They fixed it amazingly quickly as a result and it happened at 10pm as well. I was very impressed, even if it was my fault. They also had 4 engineers working on it as well untill the early hours, it was a major f*ck up I caused TBH. But all the other sites where back up within the 1st hour and that is a very rare case so there response times and at that time of night truely shows you how good they are IMO.

But the only way you can guarentee that another site doesn't take yours down due to their imcompetance is by having a dedicated server at around £99/month.

But I would check out http://www.ukhost4u.com/ for the price and what you get is just amazing IMO, cant recommend them enough, and I use them for all my sites I design.

Jaz
 
Hi Jaz

Thanks for the info, the trouble is there are so many factors that could take a site down, the thing that brought our sites down (one was dedicated, the rest VPNs) was due to routing problems, and they spent a whole day fixing it (during peak hours), I realise that some things can't be helped and technical issues are sometimes unpredictable, but try explaining that to clients! (actually they were very understanding).

I realise that when downtime happens it isn't predictable either, but 99.9% downtime covers their asses for 45 minutes a month, 540 minutes a year, and on, and on.

Recently the bbc website went down and was replaced with a low bandwidth version, what would they have done to get this working do you think?

Hmm it's certainly a puzzler for me at the mo, I really need to look more in depth at Darren's solution.
 
Yeah you are right and it does cover their ass, but 100% as you say, well....
You could do it via a 500 response then load in the file via a 302 redirect from a separate server you would however need 2 servers to do this and they both shouldn't be on the same virtual host, or technically run by the same people, that way you cover your ass if they go down across the board.

If you host 1 your self for example, and then pay for the other 1 primarily as a separate image server and then bring in the image server by some clever programming and a temporary redirect if it detects a 500 response.

I've never done it but it should work thinking about it.

Jaz
 
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