[Dovecot] Performance of Maildir vs sdbox/mdbox

[Stan Hoeppner]

On 1/18/2012 7:54 AM, Timo Sirainen wrote:
> On Wed, 2012-01-18 at 20:44 +0800, Lee Standen wrote:

>> * All mail storage presented via NFS over 10Gbps Ethernet (Jumbo Frames)
>>
>> * Postfix will feed new email to Dovecot via LMTP
>>
>> * Dovecot servers have been split based on their role
>>
>>   - Dovecot LDA Servers (running LMTP protocol)
>>
>>   - Dovecot POP/IMAP servers (running POP/IMAP protocols)
> 
> You're going to run into NFS caching troubles with the above split
> setup. I don't recommend it. You will see error messages about index
> corruption with it, and with dbox it can cause metadata loss.
> http://wiki2.dovecot.org/NFS http://wiki2.dovecot.org/Director

Would it be possible to fix this NFS mdbox index corruption issue in
this split scenario by using a dual namespace and disabling indexing on
the INBOX?  The goal being no index file collisions between LDA and imap
processes.  Maybe something like:

namespace {
  separator = /
  prefix = "#mbox/"
  location = mbox:~/mail:INBOX=/var/mail/%u:INDEX=MEMORY
  inbox = yes
  hidden = yes
  list = no
}
namespace {
  separator = /
  prefix =
  location = mdbox:~/mdbox
}

Client access to new mail might be a little slower, but if it eliminates
the index corruption issue and allows the split architecture, it may be
a viable option.

-- 
Stan