[Discuss] rsync v. cp in data migration

[vsharris at gmail.com (Steve Harris)]

Correct me if I'm wrong here, but....

1) Using a tar pipeline will (should) always be slower than a single
process (e.g., cp, cpio -p, rsync), because of the overhead of the two
processes and the system buffering for the pipe.

2) Copying to an NFS-mounted filesystem is likely to be less efficient than
alternatives (e.g., rsync) because of the NFS overhead -- it looks like a
local filesystem but in fact there is a lot of network processing happening
behind the scene.

3) I'm not an expert on rsync, but wasn't it (initially) written in a
client-server mode to achieve very high efficiency copying files over a
network?  Especially when updating (large) files which may have changed
slightly.

4) AFAIK, cp will not preserve hard links.  rsync will (though not by
default).  cpio and tar will by default.

- Steve