Re: Problem with /var/mail file > 2GB with pop3
On Mon 23 Nov 2020 at 07:24:37 (-0500), rhkramer@gmail.com wrote:
> On Monday, November 23, 2020 06:15:09 AM Sven Hartge wrote:
> > Joe <joe@jretrading.com> wrote:
> > > That's why we have IMAP, which doesn't use mbox.
> >
> > The IMAP protocal and the backend storage have no connection.
I didn't think this thread was about the backend at all, but about
where to place the emails being fetched, and hence the protocol
to use.
I don't think there's much concern about the final destination of the
emails either, but only the immediate destination, ie where emails are
placed at the moment of first arrival on the OP's system.
> Well, they do in a way -- if you use IMAP from your ISP for example, you don't
> need local storage on your email device (not any of mbox, maildir, or
> whatever).
>
> (I don't use IMAP (I use POP3), but I assume that if I were using IMAP as
> described, I could save emails on my local device, but I'm not clear on that
> mechanism / storage method.)
It may vary by client. With mutt over IMAP, opening a remote INBOX
will synchronise the INBOX's headers (only) with a local cache.¹
If and when you read a new message, mutt reads it into a cache
where each email is a separate file. That cache is to avoid having
to re-transfer the email each time you open it in your INBOX.
When you save an email on your computer, it's copied into whichever
type of storage you prefer. It might be a mailbox, meaning an mbox
or maildir (depending on how you configured it), or just an ordinary
file in the filesystem.
The main difference between a cached email and one that's been saved
to a file or mbox is that the saved one has an extra line (acting
as a separator) appended at the start, and a blank line at the end.
Two big advantages of IMAP are:
. Having looked at the header, you can delete the email without
having even transferred the body.
. While you read, save, back up, etc, your emails, they're still
safely sitting on the server. To truly delete them, you have
to flag them as deleted, and then synchronise with the server
(ie open a new folder, or close the client, or explicitly
synchronise).
Repeat, all this is for mutt/IMAP.
¹ Assuming you want a cache. IIRC this first cache is crudely
managed, gently growing all the time, and pruned just by
deleting it.
Cheers,
David.
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