[Dovecot] Quick and dirty server optimized for IMAP upload speed?

[Adam McDougall]

Early next week I need to upload over 100,000 emails to an IMAP server 
as quickly as possible from an Outlook client. I am looking for any 
methods I can use to (temporarily?) speed up the rate at which dovecot 
can accept and store IMAP uploads, whether it be storing on local disk, 
ram disk, etc.  I can setup a temporary server on a laptop for example 
and once the upload has finished I can use standard file copying methods 
to transfer the mail to stable, permanent storage.  I haven't been able 
to see over about 7 msgs/sec upload speed from a local folder in any 
mail client to dovecot (only NFS or ZFS backend tested so far with 
Maildir).  Is there something horribly wrong with the speed I am seeing 
or are there just tricks I can try?  Any tips?  I'll be working on it 
all weekend until I find something satisfactory.  It seems like I can 
upload mails to an Exchange server quicker.  I'll setup just about 
anything that my experience allows me to, I can be very resourceful with 
adhoc hardware and software.

Alternatively I'll take a fast way of converting Exchange email to a 
tree of local mbox files which I can then run mb2md on.  I tried using 
Thunderbird to Import the mails from Outlook and while it was fast, it 
messed up the formatting of some of the mails so I don't think I can use 
that.  I tried readpst briefly from libpst but it took a long time to 
run, took alot of cpu, and was spewing lots of errors so I canceled it.

Thanks for any input!