Which way to go Failover/Load Balancing/Redundant Server

[melsworld]

Hi everyone,

Until last weekend I had not thought about redundant server, backup server, failover, clustering - but guess who had one old box on floor 1 at The Planet and a new box that I was migrating to on the 2nd floor - correct me!

For those of you that missed the fun they had a major power outage which affected 9000 servers and for some people their boxes were down for up to 3+ days

So I have come to the conclusion that I need some sort of redundancy/failover provision

Whilst I do not have an unlimited budget I am prepared to go for a 2 server setup if needs be as this has impacted on my profits sufficiently to warrant it

Presently my box is used only for my sites some of which are just static page sites and others making use of databases as well. On my new box I am using cPanel

I am not selling hosting services at the present time and have no immediate plans to do so

I could do with some good suggestions on the way forward

From what I have gleaned from the various forums, if I understand it correctly load balancing would provide me with a failover situation so if server A went down server B would kick in?

Also if I have read correctly the servers could be in different data centers?

Looking at the WHM if I set up clustering am I correct in thinking that the master would upadate pages on the slave? likewise would it update database entries? - could the WHM clustering be used for boxes in different DC's

If you think that load balancing is overkill and have any other suggestions please feel free to comment

At the end of the day I need to have some set up whereby if one DC's power supply gets fried as in the case of ThePlanet I can be up and running on another box in the shortest possible time

All comments suggestions would be very much appreciated

Thanks Mel

[srobinson]

Check out this post here with someone requesting similar information
http://forums.cpanel.net/showthread.php?t=81985

tolra also stated the following on that post

One option is to have an identical copy of your site on a second server at a second data centre and send updates to the site to this backup server at some interval, e.g. every 60 minutes.

You then use a service such as http://www.dnsmadeeasy.com/ which can monitor your main IP and when it detects it is not responding updates your DNS to point to your backup server.

[sebby]

Hello Mel,

I agree with srobinson. A couple of months ago I have setup redundant accounts through dnsmadeeasy. All you need is a second box in a remote datacenter (or even a shared hosting account allowing ssh, mysql and rsync) and dnsmade easy will monitor your primary box and switch the A records when necessary (i.e. within 5 minutes when primary server fails). DNS and failover solutions are very easy to setup (watch the videos!)

The frequency at which you want to synchronize your data between the 2 servers really depends on your needs. If you are hosting very dynamic web sites (e.g. discussion forums, on-line stores), you will need to look into much more sophisticated solutions. However, for small to medium static websites, I found that a daily backup was sufficient (remember, this is for emergency only). I have been using this mirroring script that is working perfectly:

http://wiki.site5.com/Mirror_site

This option appeared to be much more easier than clustering and has practically no impact on server load (only take seconds for db and file sync). The downside is that you need to configure that for each account.

Cheers,

Seb

[melsworld]

Hello Mel,

I agree with srobinson. A couple of months ago I have setup redundant accounts through dnsmadeeasy. All you need is a second box in a remote datacenter (or even a shared hosting account allowing ssh, mysql and rsync) and dnsmade easy will monitor your primary box and switch the A records when necessary (i.e. within 5 minutes when primary server fails). DNS and failover solutions are very easy to setup (watch the videos!)

Cheers,

Seb

Took a look at dnsmadeeasy - am I correct in thinking that if you have for example 10 sites on you master box that you need to set up A records for each domain rather than just the primary domain so effectively you would be adding let's say a minimum of 2 A records per domain i.e mydomain.com & mail.mydomain.com

Thanks Mel

[sebby]

[...] so effectively you would be adding let's say a minimum of 2 A records per domain i.e mydomain.com & mail.mydomain.com

Thanks Mel

That is correct. You need to setup all the domains that you wish to monitor and each of them must contain all relevant records (A, MX, etc...). However, if your setup is the same for all your accounts (i.e. same set of records/IPs), I suggest that you have a look at their templating system in the the advanced functions. You can then easily apply the template to all the relevant domains (used that for parked domains). NOTE: As a misconfiguration can have serious consequences on the availability of your web sites, you must be familiar with DNS before proceeding - or test your config with a secondary web site).

[melsworld]

NOTE: As a misconfiguration can have serious consequences on the availability of your web sites, you must be familiar with DNS before proceeding - or test your config with a secondary web site).

Good idea testing the config with a secondary website

Thanks for your input Seb & SRobinson

Mel

[srobinson]

No problems! If you wanted another server just to test that one website on then give me a bell as it be intrested to see the outcome of this!

[Serra]

I've been messing with this a bit myself before I found this thread. One thing I've found that works really well is to setup a MASTER-MASTER replication with mySQL. That way, no matter which site is active, both sites have the same data. Then just replicate the two sites files using rsync and it's fairly easy to get working.

There are several good posts on master-master replication, but here is the one I used:

http://www.howtoforge.com/mysql_mast...er_replication