Redundancy Options Thread

[logic404]

This thread is to discuss redundancy options what were being discussed in the downtime post, including possible use of differently hosted DNS servers, and differently hosted webspace.

Please go nuts and enlighten me, guys!

[zennix]

Hi Logic,

You may want to consider a low budget round robin dns setup. This is not content distribution ala' Akamai, but it is cheap and might suffice for serious outages. Part of it would depend on you monitoring the servers and changing a setting if the main service is down.

See Microtech.co.gg for a cheap solution. They provide secondary dns services for your domain. If you knew an outage was coming, or were in the middle of one, you could point their dns service to a backup web host. It is not automatic, though I suppose you could hope that in most cases their dns service would rarely if ever be providing lookups and just leave it pointed at a secondary domain. A static IP seems to be in order here. So if the main dns lookup fails, the secondary dns should provide resolution to you backup host.

You might want to adjust the TTL of your dns servers, not sure if you can do that through matrix reseller or not. If you can, consider lowering the TTL to discourage ISPs from cacheing your lookups for too long a period.

Good luck.http://www.microtech.co.gg/dns/secondarydns.php

[Silverbug]

dont forget alot of the dns limitations are based with the hsphere system, so this may not be a posibility, unfortunaly

[logic404]

Thanks guys. It's more an "interesting topic of discussion" rather than something that I personally am liable to do anytime soon. The only guarantee I make to anyone with regards to uptime is "best effort only" - no "99% uptime" or anything. We'll do the best we possibility can, but that's it. I don't think as a reseller you can really responsibly offer anything more...

[resell01]

We are testing our custom software now, so far so good. We are going to offer this to people that need redundancy. So far, the web page part works great, trying to figure out the email area now. The best part with our software is that it is 100% automatic.

[logic404]

How exactly do you have custom software that does this? I would have thought that would just introduce another single point of failure - the server hosting the software? If not, how does it work?

[resell01]

We wrote our own website, smtp, ftp monitoring software. When it detects the website is not responding, it will switch DNS over to our other server located elsewhere. We are trying this with three different servers. Works really great for the website part. Just havnt finished up the smtp yet.

[logic404]

Aren't you still subject to the time that it takes DNS changes to propagate tho?

[resell01]

We have that worked out also, around 2 minutes.

[logic404]

Wow, I'm impressed. So, I assume this is something Matrix would have to buy and support, rather than something that we could do independently? (please excuse my spelling, i'm rather tired and sick!)

[resell01]

Actually has nothing to do with Matrix. It runs on your pc or another pc at a different location (redundancy).

Sick...know what thats like.....

[Vantage]

The thing is...
the only way to get DNS to change that quickly, it can be done, is to control the final DNS server. Set the ttl to like 60 or 30 or something. The problem with this is that your DNS server then takes a HUGE load. Normal ttl is like 4 hours to something like 2 days. This keeps a lot of the load off from the DNS server that is responsible for the domain. It makes other DNS servers cache the dns records for that amount of time.

If you cut the ttl down then your DNS server gets realy loaded down and your site appears slown because the people looking at it not only have to wait for the site to load but first they have to wait for the DNS quiry to get back. The further, in hops, the dns server is from the client the longer they have to wait.

So it is possible but you have to be in the right possition to do it and you have to be willing to put up with a delay in page load times.

James

[resell01]

Yep that is all true. To do all this, it takes good software and good hardware. This is only for people willing to pay for redundancy. The software we wrote just makes all this automatic.

Welcome aboard Vantage!

[Vantage]

I would be very interested in your program design. Your monitoring methods and the load that you generate in testing. switch over settings and the DNS server that you based this on.

It would seam like an optimal place to implement DJBDNS. What language did you write it in?? etc.

James

[resell01]

Keep in mind, this is not something we will offer all of our customers. Just the ones that need the redundancy or wants to pay for it!!!

The program is written in C#.net We are currently using it to monitor our websites here and also at two other datacenters. If a site fails, you have numerous options. You can be paged, sent an email, run a program, etc. These are independantly configured. The program can be cofigured to send an email and then it checks the account to be sure it received it ok. All kinds of options on that also. So we are not just checking pings and/or ports.

We have being using 10 test sites, and have been testing with them for about 1 month now. All is working well. Load is not an issue right now, but may become one when we get around 50-100 sites.....We will see.

Hey, you want to invest in this program