Switch to secondary IP when primary ISP is down

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pcs800

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Hello, I need to set up DNS or whatever it is that does this, to redirect exampleurl.com to a different IP address if the primary is not available. Recently one of my ISP's had a long power outage and my web site, email, message boards were not accessible for over 5 hours.

It would be nice if something detected this and forwarded visitors to another server on a working IP.

Help?
 
You seems to be considering setting up a secondary server setup, which will take up all the services when the primary goes down ? If it is a automatic switching between two ISP ip's, I suppose you need to talk with the ISP on this matter.
 
For the scope of redundancy you're looking for, you're talking about load balancing - which is complex and costly. There are a number of things that you'll have to deal with, such as data sync between servers, handling active user sessions, etc.

If you're looking for a less expensive way to do it, you could setup a cron job to sync the primary server with the secondary server nightly, and if there is a long-term interruption, you can modify your dns to point to the secondary server. (Keep in mind, you would be sending your traffic to a server that would not completely current with the primary server)

Mail is a little bit easier as long as you only want to be able to continue receiving mail - and deliver once the primary is back online. Check out this article on secondary MX for cPanel servers. It's fairly easy.
http://www.techtalkpoint.com/articles/how-to-setup-backup-or-secondary-mx-in-cpanel/

Everything I said really only apples if you manage both servers. If you are on a shared account, you would need to discuss your options with your host. If you are truly running a site in need of a high-availability solution, you should probably not be using shared hosting.
 
pcs800 - i guess we need more details as well - is this a shared account, how large is the database, files, emails, etc

secondary DNS helps if the issue was primary DNS - but if you have a network outage in the data center - it does not matter and your site wont be accessed --

give us more details and i think i can give you some advice to do this on the cheap side
 
It appears you're looking for DNS Failover.

Check out http://www.dnsmadeeasy.com

You can do this yourself (if you have the servers available), but for a small fee, you can use the company listed above to handle it for you.

I have no association with the above URL. I have read many great reviews on them, however I have never used their service.
 
DNS Failover only goes as far as sending traffic to an alternative server, which is what the original poster is asking, but I'm not sure if he/she has thought about synchronizing the data on both systems.

Do you already have some sort of synchronization set up, pcs800?
 
Sync'ing the information would probably be the best method, however as a quick solution even putting up a static page to say "we're having trouble, come back soon" is much better than a 404 or non resolving page.

Also - rsync is great for sync'ing up sites (static pages). From a Database end of things, requires a little extra tweaking. The only issue at that point would be after you've gone from "A" to "B", when "A" comes back online, the information must be sync'ed back and can create a nightmare.

Load balanced machines take care of this - and it's even possible to setup load balanacing through multiple data centers.

Personally I'd setup a server with a database only. Then use two other sites/servers to access the database - thus information is always available. Then you just have to make sure that the mysql server doesn't go offline ;)
 
If your site is important enough that you want it online 100% go for a load-balancing setup. If it's not important enough to spring for load-balancing then chances are you'll survive a little downtime.

I'm not trying to be rude here, but you're not going to get what you need for "cheap" or "free" so if your budget isn't reasonable then you will have to find some way to handle downtime that is less expensive but then again not such a great option overall such as manual/automatic DNS failover and manual/automatic data replication usually via CRON.
 
handsonhosting said:
It appears you're looking for DNS Failover.

Check out http://www.dnsmadeeasy.com

You can do this yourself (if you have the servers available), but for a small fee, you can use the company listed above to handle it for you.

I have no association with the above URL. I have read many great reviews on them, however I have never used their service.
Click to expand...


I second this.. great way to set up redundancy between two servers residing on two separate networks. You can even manage loads with dns roundrobin style.
 
It appears you're looking for DNS Failover.

Check out http://www.dnsmadeeasy.com

You can do this yourself (if you have the servers available), but for a small fee, you can use the company listed above to handle it for you.

I have no association with the above URL. I have read many great reviews on them, however I have never used their service.
Click to expand...

I third this. It is a good way to make sure you have 100% uptime.
 
pcs800 said:
Hello, I need to set up DNS or whatever it is that does this, to redirect exampleurl.com to a different IP address if the primary is not available. Recently one of my ISP's had a long power outage and my web site, email, message boards were not accessible for over 5 hours.

It would be nice if something detected this and forwarded visitors to another server on a working IP.

Help?
Click to expand...

If it was ISP issue (downtime) ..I dont feel even a secondary IP would have helped you in that case.
 
webhost.uk.com said:
If it was ISP issue (downtime) ..I dont feel even a secondary IP would have helped you in that case.
Click to expand...

I think he might mean a secondary IP at a different location.

100% uptime isn't something that comes cheap. What I will say is that he definitely shouldn't expect 100% uptime in any shared hosting scenario.
 
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