Hey,

The first part I didn't quite understand "In these mining pool, can it be extracted with GPU?"
--> You cannot extract data with a GPU, you need the private key to find all your little pieces of data distributed among the nodes that keep the data (Storagenodes are what we call them)

This part "And in the case of the sale of storage, the vendor at some point should guarantee 100% of the availability of this storage, that is, always connected  and switched on the cluster or the machine?"
Is clear..
--> A vendor needs to keep his machine on online almost all the time, if the machine goes offline too long he will lose the data because it will be reconstructed on another node (or nodes, no guarantee that those blocks will all be moved to the same new node). If all the data is gone he will start again as a new node and collect new blocks from other data..
The system by itself is a big cluster, all data is send to 10 different machines located as far apart as possible. That way you will not have all nodes in a same physical location which is of course not wanted in this setup. 6 of those machines can go offline before the system gets critical, but that will be very difficult to reach because the more nodes go offline the faster the data will be reconstructed somewhere else.

Did I answer your question a little?

If you need more info just ask