Re: imapsync's --maxage flag

[Tom Golson <tgolson@tamu.edu>]

Hi John,
	Heh.  Yes, there was.  That's one of the reasons we kept a sliding
window with the --minage flag: to try and minimize the number of
messages that customers would be modifying during preparations for the
migration.  We started out with a minage of 30, I believe, then worked
that down to 14 once we'd gotten the bulk of the "historical" mail
copied and then in the final two weeks we shortened that down to 7, with
the goal being that for the 12 hours we were going to be down, we'd be
migrating only the last week's worth of mail.
	Generally, our philosophy was that if the mail's been in your mailbox
for 2 weeks, there's a good chance it's in whatever folder you plan on
ignoring it in for the message's lifetime.  Obviously, that's not true
for everyone, but we didn't have very many complaints.
	The complaint we did have was from maybe a half-dozen customers who
went out two or three days before the final migration, deleted the last
5 years worth of mail they decided wasn't really critical and then were
a little bent when the logged into the new system and it was all there
again.  You move that much mail, and someone's going to be unhappy about
something.  We tried to keep it all in perspective. :-)

--Tom

John Fulton wrote:
> Tom Golson wrote:
>> 	This is pretty much the technique we used to migrate 66,000 accounts
>> and about 5 TB of mail.  It seemed to work pretty well.  For the first
>> iteration, we actually used only the --minage flag.  Then during
>> subsequent iterations, until the final migration which was with --maxage
>> only, we migrated sliding windows of mail using both the --minage and
>> --maxage flags. ... I seem to recall our first synch took about a week or a
>> week and a half, and our minage was 30.
> 
> Tom,
> 
> Was there any concern over missed operations on the old mail system?
> 
> If a message older than t days is modified in some way (moved, deleted,
> etc) when imapsync is run with maxage less than t, then that operation
> is not migrated. E.g. I delete a message from January after that portion
> has been synced so post migration I have to delete it again.
> 
> I see this as a reasonable trade off so that the migration can happen in
> a reasonable amount of time but I'm trying to work out how to plainly
> explain this to users. You mentioned "sliding windows of mail" did this
> involve a hiatus on email archiving or requesting that users do any
> cleanup of old mail prior to a certain date to ensure that it's not
> imapsync'd?
> 
> I was glad to see your reply. Thank you!
> 
>   John