[Dovecot] Architecture for large Dovecot cluster

[Stan Hoeppner]

On 1/24/2014 6:24 AM, Javier de Miguel Rodríguez wrote:
>  
> 
> Great mail, Stan 
> 
> Another trick: you can save storage (both space & iops) using mdox and
> compression. CPU power is far cheaper than iops , the less data you
> read/write, the fewer iops. 

Yeah, the cost of enterprise storage is insane.  But I'd be wary of
using compression on primary storage with 50K concurrent IMAP users plus
5K POP users.  Even with dozens of cores of horsepower it'll still add
latency.  For alt storage sure.  Using compression on primary storage
would make system sizing much more difficult WRT core counts, clock
speed, and memory requirements.  And it would need much load testing.

> You can use gzip,bzip2 or even LZMA/xz compression for LDA. If you also
> use Single Instace Storage and Alternate (cheap) storage for old mail,
> you can save a lot of money in storage. Also consider using mdbox + ssd
> for indexes (hp storevirtual VSA+ a couple of ESXi with ssd disks will
> give you real-time replicated ssd iscsi lun for indexes)

I don't know how much SIS would benefit an Australian service provider.
 I don't know the culture, people's "forwarding" habits.  If it's like
parts of The States it may help some.  Alt storage definitely would.  To
me your SSD suggestion just puts extra write wear on the SSDs.  A form
of SAN flash cache would be better.  In the case of the VSAs they have
tons of memory, 12 slots, to having fast hot indexes probably wouldn't
be an issue.  But obviously the HP gear isn't the only game in town.

-- 
Stan