mailutil - Can't open mailbox

[Carlton T]

Hi, I have just joined the group, so forgive me if this problem has been addressed before, I did search the archive with no success. I have a client with a number of HUGE mailboxes, some in excess of 16 Gigs. As you can imagine, the server slows down to a crawl when acessing these mailboxes. I am trying to use the mailutil's prune option to remove messages from one of the 16 Gigs mailboxes, but I get the error message "Can't open mailbox <mailbox_name>: no such mailbox". However, if I perform the same operation against a mailbox which is approx 4 Gigs, it completes successfully. I have done a little debugging and noted that the error message is being generated by the open_mail function within the module mail.c. Has anyone else attempted this on such a large mailbox file? Is there a limit on the size of mailbox file that can be handled by mailutil? Am I wrong in assuming that the problem is related to the size of the file? Any help/pointers greatly appreciated. -- Carlton

[Tim Mooney]

Post by Carlton T
Hi, I have just joined the group, so forgive me if this problem has been
addressed before, I did search the archive with no success. I have a
client with a number of HUGE mailboxes, some in excess of 16 Gigs.

What format are these mailboxes in? Traditional UNIX "From " style?

I don't know if it was ever addressed, but UW imapd used to have a 2 GB
folder limit for traditional format mailboxes. That had to do with the
size of a signed 32 bit quantity. Perhaps that's changed, but either
way, I would be very surprised if it supported traditional folders larger
than 4 GB. Moreover, performance would likely be horrible.

Post by Carlton T
As
you can imagine, the server slows down to a crawl when acessing these
mailboxes. I am trying to use the mailutil's prune option to remove
messages from one of the 16 Gigs mailboxes, but I get the error message
"Can't open mailbox <mailbox_name>: no such mailbox". However, if I
perform the same operation against a mailbox which is approx 4 Gigs, it
completes successfully. I have done a little debugging and noted that
the error message is being generated by the open_mail function within
the module mail.c. Has anyone else attempted this on such a large
mailbox file? Is there a limit on the size of mailbox file that can be
handled by mailutil? Am I wrong in assuming that the problem is related
to the size of the file? Any help/pointers greatly appreciated. --

You're very likely correct that it is related to the size.

The problem for you is that UW imapd is essentially abandoned, at this
point. The UW staff that worked on it have been forced to move on to
other things. The primary author, Mark Crispin, has a fork of UW imapd
called Panda IMAP. If you're going to stick with something UW-ish, you
should be looking at that.

Even if you go to UW imap, you should expect to have to convert to some
other format (likely MIX).

If you want to stick with traditional mailbox formats and you need to
support really large folders, you should investigate dovecot.

Tim

[Mabry Tyson]

My largest mailbox is 12GB (280K messages).

If you aren't using the MIX format, you should. See
http://www.washington.edu/imap/documentation/mixfmt.txt.html
You can convert with mixcvt (*not* mailutil).
The mix format stores a mail folder in a directory, with individual
files no larger than a certain limit (except where a single message is
larger than the limit). Access & update will be incredibly faster, and
much less of a load on the system.

Mixcvt is a separate download, if I recall correctly.

If the 16GB mail file is in mbox format ("traditional Unix mail
format"), then I can imagine all kinds of problems.
If mixcvt can't deal with it, then you'll have to use something like
split, with hand editing to break it into manageable sizes and to break
between messages.

Post by Carlton T
Hi,
I have just joined the group, so forgive me if this problem has been
addressed before, I did search the archive with no success.
I have a client with a number of HUGE mailboxes, some in excess of 16
Gigs. As you can imagine, the server slows down to a crawl
when acessing these mailboxes. I am trying to use the mailutil's
prune option to remove messages from one of the 16 Gigs mailboxes, but
I get the error message "Can't open mailbox <mailbox_name>: no such
mailbox". However, if I perform the same operation against a mailbox
which is approx 4 Gigs, it completes successfully. I have done a
little debugging and noted that the error message is being generated
by the open_mail function within the module mail.c.
Has anyone else attempted this on such a large mailbox file? Is there
a limit on the size of mailbox file that can be handled by mailutil?
Am I wrong in assuming that the problem is related to the size of the
file?
Any help/pointers greatly appreciated.
--
Carlton
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