zdb: nsswap as alternative to reload workflow #136
Description
In order to reload a namespace modified underneath (with a FREEZE), that will require some downtime and locking.
In case some namespace can be rebuilt online, an alternative to that would a way to swap two namespaces. Example: creating a new namespace, fillin with wanted data then atomicly swap original namespace with the new one (rename directory and update index pointers). This would require no downtime and would be easy to implement.
To investigate. Can be used on the hub to cleanup the namespace online.