dovecot - Aug 2017 - General IMAP question

My server is a limited space mailserver set up to filter spam.  Most of it's
mail is passed on ot an exchange server so it is not stored locally.  I have a
handful of pop accounts that are stored locally.  For years I've used mbox
type mailboxes that I'm familiar with and can access on the server when
needed using the old mailx program.  They use a variety of clinets, typically
Outlook and smartphones.

I'm considering changing to IMAP because I need a single IMAP mailbox for an
unrelated reason.  But I am concerned about user storage issues at least..

Currently my POP users have a max mbox size but that is how much it will store
before they "come get it".  I ensure they have at least one device set
to delete from the server periodically (i.e. 1 week).  So users with multiple
devices get their mail duplciated on their devices and at least one devices
keeps the server emptied so their mbox does not hit any limits.

As I understand it, when using IMAP, the user's messages are perpetually
stored on the server.  So if the user is not moving their messages from their
inbox to some other place (e.g. a different Outlook pst file), that all the
messages will remain on the server.  All messages are "synced" in the
user's inbox or other user created folders.  Is that right?  This would
pretty quickly cripple those normal non-computer types that have years of emails
in their inboxes.  And I don't have the storage space to allow storing years
of their mail.  I also understand if they exceed their storage limit, mail
starts bouncing which is what's I'd expect.

At first I started googling how to expire the old mail, but then realized that
won't work because if I delete on the server, I understand that will delete
on their devices, too.

How do other's deal with this?  Am I misunderstanding something?  As popular
as it seems to be, these seem like big hurdles to overcome.  Appreciate some
help for a IMAP noob.

Thanks,
Scott

On 2017.08.31. 22:42, Scott Techlist wrote:
> My server is a limited space mailserver set up to filter spam.  Most of
it's mail is passed on ot an exchange server so it is not stored locally.  I
have a handful of pop accounts that are stored locally.  For years I've used
mbox type mailboxes that I'm familiar with and can access on the server when
needed using the old mailx program.  They use a variety of clinets, typically
Outlook and smartphones.
> 
> I'm considering changing to IMAP because I need a single IMAP mailbox
for an unrelated reason.  But I am concerned about user storage issues at
least..
> 
> Currently my POP users have a max mbox size but that is how much it will
store before they "come get it".  I ensure they have at least one
device set to delete from the server periodically (i.e. 1 week).  So users with
multiple devices get their mail duplciated on their devices and at least one
devices keeps the server emptied so their mbox does not hit any limits.
> 
> As I understand it, when using IMAP, the user's messages are
perpetually stored on the server.  So if the user is not moving their messages
from their inbox to some other place (e.g. a different Outlook pst file), that
all the messages will remain on the server.  All messages are "synced"
in the user's inbox or other user created folders.  Is that right?  This
would pretty quickly cripple those normal non-computer types that have years of
emails in their inboxes.  And I don't have the storage space to allow
storing years of their mail.  I also understand if they exceed their storage
limit, mail starts bouncing which is what's I'd expect.
> 
> At first I started googling how to expire the old mail, but then realized
that won't work because if I delete on the server, I understand that will
delete on their devices, too.
> 
> How do other's deal with this?  Am I misunderstanding something?  As
popular as it seems to be, these seem like big hurdles to overcome.  Appreciate
some help for a IMAP noob.
> 
> Thanks,
> Scott
> 
Use that single mailbox with IMAP, others stay to POP(if server with 
such small disks pretends to be a mailserver). It's just connection 
protocol at all.

-- 
KSB