[Dovecot] Scalability plans: Abstract out filesystem and make it someone else's problem

[Ed W]

Timo Sirainen wrote:
> On Wed, 2009-08-12 at 15:42 -0400, Charles Marcus wrote:
>   
>>> - and I've never heard of any other mail server supporting such a
>>> thing.
>>>       
>> Exchange does... and is the single and only reason I have *considered*
>> switching to it <shudder> in the past few years...
>>     
>
> I heard that the next Exchange version drops that feature, because it
> typically causes more disk I/O when reading. I don't know if it's still
> possible to enable it optionally though.
>
>   

It also had a bunch of limitations, it was basically only single 
instance for CC recipients on a message (more or less).  Quite a lot of 
things such as certain types of virus scanning would (I think) easily 
disable the single instance storage also?

So I doubt it would help in most of the cases mentioned here, ie each 
time it was re-forwarded internally it would not be single instanced

I still think it would be instructive to do some benchmarks though - 
often these things look good on paper, but are surprisingly less 
effective (given the implementation cost)  when measured.  I'm not 
disagreeing, just would be interested to see some numbers...

I think perl's Mimetools would make it pretty easy to build something 
which scanned all files and created a hash of all interesting 
attachments.  Quite possibly there is an even more clever way to get the 
same through misusing some Dovecot feature?

Good luck!

Ed W