Let's say an Exchange DB exists on a 100GB drive.
The DB itself gets up to 50GB on the first day, then users delete 10GB of data from their mailboxes over the course of the day.
From my understanding:
i. Online maintenance runs at the set interval > but what does this actually do in terms of whitespace? I've read around but not sure. As far as I understand, the online maintenance reclaims the space from the database and defragments the DB so that that whitespace ('free' space but within the DB itself) can be used by Exchange for more data, rather than expand the EDB file itself.
ii. Online maintenance logs 1221 Event ID - this shows how much space Exchange has recovered from removing deleted items and now exists as whitespace in the EDB? That is, if offline defrag or mailboxes were moved, then this is the 'true' size of the DB?
iii. How does this all work with SCR/CCR? Would I expect the EDB sizes on the DB on the target side to be the same as the size of the EDB on the source side? Or would they be this size minus the whitespace?
iv. Is there any special way to treat whitespace with CCR/SCR? Normally, if it looks like the DB is getting too big for the drive and we know we have a lot of whitespace, we move the mailboxes to a spare store, delete and recreate the EDB, then move the mailboxes back and reseed. Can we do anything special on CCR clusters?