Choose a recovery deadline for temporary Celestia Fibre shards
A Fibre blob ID can remain in an application database after the protocol's shard-retention period. A recovery service needs an independent copy before the retention guarantee runs out.
Calculate from promise creation
Read shard_retention for the applicable network. The documented retention endpoint is the later of promise creation plus that duration and promise expiry. In the example a 10:00 creation time with four hours of retention gives 14:00. Set the archival job early enough to allow another download and verification attempt.
created 10:00; retention parameter 4 h; promise expiry 11:00
retention endpoint = later of 14:00 and 11:00 = 14:00
Exercise the independent copy
Download by the full Fibre blob ID, verify the application envelope and store its bytes with the identifier. Restore from that copy without contacting the shard servers. Successful downloads after the calculated deadline are observations of continued service and cannot extend the protocol guarantee.