Hello,

I'm a system administrator for a small research group. Our group has a
lot of mail roughly 16 gigs worth for 10 users. I'm desperately trying
to get off our Exchange 5.5 server and migrate to a
FreeBSD/Postfix/Courier-IMAP mail server.

The problem is the migration part. My users collaborate with other
scientist, and they have rather large data sets they email to each
other. Not good, but it is what it is and ofcourse I have to deal with
it. Anyways, I've been trying to use imapsync to copy the mailbox over
and it seems that there's roughtly a 33 meg limit on the message size.

---
$ imapsync --host1 exchange --user1 mike --passfile1 mike.pass --host2
courier --user2 mike --passfile2 mike.pass --split1 100 --split2 100
....
Copied msg id [8155] to folder INBOX.Sent Items msg id [6592]
+ NO msg #8156 [5YgB8nPpAEu0df0lmcxXnQ:25308502] in INBOX.Sent Items
+ Copying msg #8156:25308502 to folder INBOX.Sent Items
Out of memory during "large" request for 33558528 bytes, total sbrk()
is
514009088 bytes at
/usr/local/lib/perl5/site_perl/5.8.7/Mail/IMAPClient.pm
line 1714.
---

Has anybody done this before? and Can someone point me in the right
direction on how to get this done?

Thanks,
Howard

I guess I should have provided a little detail on the imapsync I'm
using...

$ imapsync --host1 exchange --host2 courier --justconnect
$RCSfile: imapsync,v $ $Revision: 1.172 $ $Date: 2006/05/09 23:06:29 $
Mail::IMAPClient version used here is 2.2.9
Here is a freebsd system (FreeBSD courier 6.1-RC FreeBSD 6.1-RC #0: Tue
Apr 25 15:06:01 PDT 2006 user@courier :/usr/obj/usr/src/sys/SMP
i386)
with perl 5.8.8
>From software : * OK Microsoft Exchange IMAP4rev1 server version
5.5.2658.25 (exchange) ready
>From capability : IMAP4 IMAP4rev1 IDLE LITERAL+ LOGIN-REFERRALS
MAILBOX-REFERRALS NAMESPACE AUTH=NTLM
To software : * OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE
THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION
STARTTLS] Courier-IMAP ready. Copyright 1998-2005 Double Precision,
Inc. See COPYING for distribution information.
To capability : IMAP4rev1 UIDPLUS CHILDREN NAMESPACE
THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION
STARTTLS

howard.tan@gmail.com wrote:
> Hello,
>
> I'm a system administrator for a small research group. Our group has a
> lot of mail roughly 16 gigs worth for 10 users. I'm desperately trying
> to get off our Exchange 5.5 server and migrate to a
> FreeBSD/Postfix/Courier-IMAP mail server.

HI.

I would like to suggest an additional approach.
You can export all mailboxes from MS Exchange to PST files (using MS Outlook or Exmerge),
store one copy on the user PC,
and additional copy on a file server for backup.

Then you start using the new IMAP server without importing all the old emails,
and users will have access to their old emails from the PST file.

There are obvious pros and cons for such approach, but at least you should consider it.

Yizhar Hurwitz
http://yizhar.mvps.org