Using my IPFS node, I uploaded files to the network which became accessible via ipfs.io HTTP requests. After a few days I noticed that these files are no more accessible.
I know that this is due to garbage collection, but my questions are:
Does IPFS public gateways retrieve data automatically from ipfs nodes?
How much time it takes to get the content disappeared?
They don’t retrieve any data unless someone requests it. It became accessible accessible via ipfs.io just because you, or someone else, requested it.
Here’s an experiment you can do to verify this behavior. Add a unique file to your local IPFS node and pin the hash. Leave that node running for a few minutes, hours or days. Stop your local node and try to retrieve the file via ipfs.io. You won’t be able to.
It depends on the configuration of the gateway node.