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

[Timo Sirainen]

On Aug 28, 2009, at 8:38 PM, Adam McDougall wrote:

> 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.

 From Dovecot's side the only thing you can do is fsync_disable=yes.  
The main problem is probably network latency, because Outlook doesn't  
support MULTIAPPEND extension (and perhaps not even LITERAL+  
extension?) Did you already try running Dovecot on the same computer  
as Outlook (some virtual thingy or maybe it works in cygwin)?

> 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.

If the mails are in Exchange, can't you connect to it using IMAP?