Hi, everyone.
I'm trying to read the source code that boots an OSD instance, and I find something really overwhelms me.
In the OSD::init() method, it read the OSDSuperblock by calling OSD::read_superblock(), and the it tried to get the "current" map : "osdmap = get_map(superblock.current_epoch)". Then OSD uses this osdmap to calculate the acting and up set of each pg.
I really don't understand this! Since the OSDSuperblock is read from the disk, the superblock.current_epoch should be an old epoch which is recorded by the last OSD instance that run on this directory. Why use an old "current_epoch" to calculate the acting and up set of each pg?
Please help me, thank you:-)
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