|FID sequence. |
|FID number within sequence. |
|FID version, used to distinguish different versions (in the sense of snapshots, etc. |
FID is a cluster-wide unique identifier of a file or an object (stripe). FIDs are never reused.
Sequence is a unit of migration: all files (objects) with FIDs from a given sequence are stored on the same server. Lustre should support 2^64 objects, so even if each sequence has only a single object we can still enumerate 2^64 objects.
FID version, used to distinguish different versions (in the sense of snapshots, etc.
) of the same file system object. Not currently used.