1. Which one is better? dedicated hosting or colohosting?
2. what should i do if my server is ran out of space? how about the data then? let's say if i have email server running on my server and I have only 40gb space of hd. It is ran out space and I buy a new hd and install it on my server. But then how to set it up so that if the space is not enough the server will automatically assign to a new hd? if the data stored separately, how can the software know the data is in the old hd or in the new hd?
3. I've heard that site like ebay or microsoft.com are running multiple server to prevent that site down? how this is work? does it work using multiple nameserver (eg. ns1.abc.com, ns2.abc.com,ns3.abc.com, ns4.abc.com with different ip address in different server for each) so that if ns1 and ns2 of abc.com down, the browser will automatically go to ns3 and ns4? so how about the data then? that means the server have to copy the data to back up server everytime it gets updated to make it showing the exact thing?
so how do load balancing works? is there any simple way to do it? how about the idea of nameserver like i mentioned above?
also if i want to change nameserver to other... is there any way to prevent my site to be not accessible? may be i can show one page showing that this site is now under regular maintenance or something like that?
3. Simple load balancing is done with DNS or some type of a network device that can distribute the load to many servers behind it. You need to share the same data on all servers and it has to be up to date.
Complex load balancing uses other special hardware that can do global geo balancing, and your data is cached on those devices. This hardware is smart enough to detect a content burst and redirect traffic to closest location. It also serves the content from the server physically closest to the client.
Some also use third party network caching services like Akamai.
Originally posted by edyonline so for example, someone put a new listing on ebay it means that that listing is automatically stored at all servers?
I would say that eBay listings are stored in a MySQL database which would be running across multiple servers that only serve the MySQL part. They probably all mirror each other so the load is distrubuted.
Ebay has front end servers and back end servers (at least).
Front ends are web servers, and back ends are database servers. Front ends don't need to know anything about content, they talk to database. Database is probably Oracle on Solaris, clustered in some way, and with real-time failover features, and so on. When you sell something, it inserts it into the back end database, which then gets replicated all over probably.