What does pinning mean?
Pinning a file is done with the following command:
siac skynet pin [skylink] [destination]
If you pin a file, you are saying "I want the file to stay online even if no one else does".
Pinning a file means that you have uploaded it and are paying for it to stay available on the network. All uploaded files are managed by contracts formed with the hosts that store the data.
You typically pay in three-month chunks, so as long as you open your Sia node once in a while (before contracts expire), the payment will refresh and the file will stay pinned. As long as a file is pinned, it is accessible to anyone who has that file’s link.
Anyone who has access to a file can choose to re-pin the file. This will cause the file to be uploaded to their hosts and secured under their file contracts. This ensures that the file will remain available on Skynet even if the original uploader deletes the file or fails to renew their contracts. Importantly, the skylink will not change even if the set of hosts seeding the file completely rotates out. Everyone who had access to the original skylink will continue to be able to access the file even if the set of hosts and users pinning the file completely changes.
A few other good things to know about pinned files:
- Internal skylinks are links that you have pinned
- External skylinks are links that have been pinned by someone else
- As long as one person is pinning a file, any Skynet portal can fetch it