[Apparently, many don’t know how to do this (including many in the ‘GSC’, reportedly) so I thought I’d share.  This is useful for those (such as myself, at the moment) with WAN capacity issues]

In order to account for the size of the next snapmirror transfer:

1.)        Calculate the delta in ‘df’ output from source and destination (source used minus destination used)

2.)        Calculate the sum of space used for all snapshots since (and including) the most recent snapmirror snapshot (the baseline).

(this can be done most easily using Filerview, or if you really want to do some math use the ‘own blocks’ output via priv set diag; snap status)

Add the two totals together and you’ve got your next snapmirror transfer size.

Enjoy,

Glenn