Apparently, there are two ways of doing it;

1. Through TP's load balancing service, which is :a. Not reliable, b. Expensive
2. By getting another server, installing some load balancing server on it (ldirector or something), which is : a. not 100% bullet proof since there's still 1 single point of failure (the new load-balancing-server), and b. stil expensive

Is there any 3 party load balancing solution that could be used on top of a couple of servers hosted with SM ? Some external load balancing service maybe ? Anything ?

Tks,
MC

Are you talking load balancing or failover redundancy?

You could set up some sort of round robin dns system at a third party DNS host which would possibly give you load balancing.

If you coupled that with some sort of heartbeat failover, you should be sorted.

Failover.

How would i integrate round robin -which simplly cycles through IPs- with a heartbeat monitor ?

Sorry but your answer is a bit vague, can you explain by mentioning a bit more specific examples of software or steps on how to do this ?

Appreciated.

MC

Check out the services at http://www.zoneedit.com/doc/faq.html

I think thats what you are trying to acheive.

DNS roundrobin works on the DNS level, it doesn't involve your servers at all. What happens is when a person tries to resolve your domain, they randomly get one of a set of IPs you specify. This leads to your load being balanced because a roughly equal number of customers go to each IP.

DNS roundrobin does not do any failover.

I have been using heartbeat and ldirectord for more than a year in my SM and TP servers. Take a look at www.ultramonkey.org. You can implement load balancing and high availability with just two servers. If one goes down, the other one takes its IP addresses and nobody notices the glitch.

Caveat: all the servers must be in the same subnet and preferrably you should have a private switch interconnecting them through second NIC cards. I managed to buy this from SM and TP. Ask them for all the servers to be in the same subnet. I.e.: if you buy 3 servers, insetad of 3 separate /29 blocks, ask for one /28 block and put all the servers there. You have to explain it over and over again to the sales people but eventually they will understand.

This solution works fine as I can take down servers without any downtime. FYI, I am using the Streamline Load Balancing and High Availability topology as described in www.ultramonkey.org.

Nicolas

Interesting. How much does a private switch cost and how does one go about purchasing the service? Do you ever get problems with arp clashing?

I pay $25 per private switch and in TP I had to pay $10 monthly for each additional NIC card. No problems with ARP. Heartbeat manages that. I've had some problems in the past which ended up in two servers being active at the same time or also one time none of them were active. However, after fine tuning heartbeat configuration it has been running smoothly.

One thing to take into account is that you will end up using more bandwidth than in a normal situation. Incoming packets will go first to the director and then to the real server, so for all the packets which need to be redirected you will pay 3 times the bandwidth. However, it is only for incoming packets, not outgoing ones, which are usually the bigger ones. Before the end of the month I usually move the active director from one server to another one to avoid going over the 2000GB limit.

It is easier to implement if you are running the 2.6 kernel, as you need no patches and there is no need for arptables.

Seems great!

Altought I must have only Windows servers. (my app. runs in ASP/ASP.NET)
Could this be possible? Using cygwin perhaps?

For Windows, I would look into getting a copy of Windows 2003 Enterprise on the server and then using Windows 2003 CLustering Service.

*EDIT* I take that back, you may have the equipment to do it now.

Start Reading (MIcrosoft Word compatible client required)

You can use linux for load balancing and HA as a frontend and have your windows servers in the backend. You will need two additional linux servers though.

I would look at NLB before going to all the trouble of Linux servers....

I've been reading about NLB and I'm pretty amazed.
It seems to be a very good (and cheap) option for Windows-based users. I will make further investigations about this option, but it might be the solution of my problems.

Some more interesting links:

http://www.microsoft.com/technet/prodtechn...ing/nlbfaq.mspx
http://www.west-wind.com/presentations/loa...Windows2003.asp
http://www.microsoft.com/technet/prodtechn...1989aeac74.mspx