Re: imapsync's --maxage flag

[Tom Golson <tgolson@tamu.edu>]

Hi John,
	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.
	Our only problem was getting IMAPS connections to work, so we ran it
all over stunnel, which was a bit of a performance hit, but still
manageable.  I seem to recall our first synch took about a week or a
week and a half, and our minage was 30.

--
Tom Golson
Senior Lead Systems Engineer
Open Systems Group
Computing & Information Services
Texas A&M University

John Fulton wrote:
> 
> I need to imapsync 5,000 accounts totaling 800G of mail. Has anyone used
> imapsync's --maxage flag to speed up an imapsync? If so, any problems?
> 
> If you're going to have repeated runs on imapsync it seems that you can
> shrink the time for each sync by setting --maxage to the number of days
> between the start and end of the previous imapsync.
> 
> I did an early test. It took me 50 minutes to imapsync 450M of mail even
> if run repeatedly every hour. However if I run a second time with
> "--maxage 1", i.e. sync only messages from the last day, then it took
> only 3 minutes. This is only for a single user but I expect this trick
> to ease my migration.
> 
> I expect the first sync to take a long time: let's assume n days. After
> that I would sync again but with maxage at n and then I expect n to
> decrease for each call.
> 
> imapsync
> imapsync --maxage n
> imapsync --maxage n=time(previous_call)
> ...
> imapsync --maxage k
> 
> Finally k would be either the outage window OR the time users must wait
> for the last set of messages between k and today for all of their mail
> to finally be cut over after go live. You would have a good idea of what
> k would be after repeated runs with no change in n.
> 
> Has anyone tried this?
> 
>   John