How IPFS duplicates data?

Hi everyone,

Could you please guide me if we use IPFS for data(file,text,etc.) sharing, whether the files will be duplicated on other people’s disks? And if so, do other people’s file get stored on our system? How should I test it and be sure about it?

And what is the cost for sharing data?

Many thanks in advance,

Please check out the EC(erasure coding) entry in wikipedia. There’s the detailed explain about it.Or there’re some issues about EC