"Availability" means being able to access the blockchain/system/network and get the data you want, when you want it.
The way most blockchain systems find out which nodes are on the network is usually through a gossip protocol, so typically your app will start off with some "seed nodes", which it contacts, then gets information about other nodes on the network.
Once you have the IPs of say 100 nodes scattered around the world, on different networks, running different OSes, etc. the chances of losing access to all those nodes is virtually zero.
Edit: You seem to be thinking about blockchains in terms of how traditional cloud/web based systems work. That's the wrong way to think about it. Blockchains have fundamentally different architecture. They do not use load balancers.
I won’t labour the point but you’re mistaken, nodes ARE traditional cloud/web based systems. All you have to do is check https://www.ethernodes.org/network-types to see that, 65% of Ethereum nodes are hosted and 25% of those are on AWS. Blockchain is built on existing infrastructure, there is no silver bullet availability it’s offering.
"Availability" means being able to access the blockchain/system/network and get the data you want, when you want it.
The way most blockchain systems find out which nodes are on the network is usually through a gossip protocol, so typically your app will start off with some "seed nodes", which it contacts, then gets information about other nodes on the network.
Once you have the IPs of say 100 nodes scattered around the world, on different networks, running different OSes, etc. the chances of losing access to all those nodes is virtually zero.
Edit: You seem to be thinking about blockchains in terms of how traditional cloud/web based systems work. That's the wrong way to think about it. Blockchains have fundamentally different architecture. They do not use load balancers.