[Go-essp-tech] Reasoning for the use of symbolic links in drslib

[Kettleborough, Jamie]

Hello Karl, everyone,


	For replicating the latest version, I agree that your alternate
structure poses difficulties (but it seems like there must be a way to
smartly determine whether the file you already have a file and simply
need to move it, rather than bring it over again).   
	 

Doesn't every user (not just the replication system) have this problem:
they want to know what files have changed (or not changed) at a new
publication version.  No one wants to be using band width or storage
space to fetch and store files they already have.  How is a user
expected to know what has really changed?  Estani mentions check sums -
OK, but I don't think all nodes expose them (is this right?).  You may
try to infer from modification dates (not sure, I haven't look at them
that closely).  You may try to infer from the TRACKING_ID - but I'm not
sure how reliable this is (I can imagine scenarios where different files
share the same TRACKING_ID - e.g. if they have been modified with an nco
tool).
 
Is there a recommended method for users to understand what *files* have
actually changed when a new publication version appears?
 
Thanks,
 
Jamie
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