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Hi!
On Thu, Aug 12, 2010 at 1:54 PM, David Lang
<david.lang@xxxxxxxxxxxxxxxxxx> wrote:
> On Thu, 12 Aug 2010, Timo Schoeler wrote:
>
>> thus David Lang spake:
>>> I missed the beginning of this thread
>>> On Thu, 12 Aug 2010, Timo Schoeler wrote:
>>>
>>>> -----BEGIN PGP SIGNED MESSAGE-----
>>>> Hash: SHA1
>>>>
>>>> thus Jose Ildefonso Camargo Tolosa spake:
>>>>> Hi!
>>>>>
>>>>> On Wed, Aug 11, 2010 at 3:56 AM, Faisal Ghulam <f.ghulam@xxxxxxxxxx>
>>>>> wrote:
>>>>>> I want to deploy LVS for highly traffic IMAP,POP3 .
>>>>>>
>>>>>> Can any one guide me how to get it with Centos 5.3.
>>>>>>
>>>>>> My backend Email server is Postfix.
>>>>> Postfix handles SMTP, not IMAP/POP3. I use dovecot for IMAP/POP3, but
>>>>> I'm more interested on security than performance, so..... maybe
>>>>> someone else can suggest a faster IMAP server (although dovecot is not
>>>>> slow, I think, just for the record).
>>>> Dovecot is one of the best performing (if not *the* best performing)
>>>> pop/imap servers out there. Just use the search egine you like for
>>>> benchmark comparisons, and you'll get a bunch of results that will show
>>>> this, on different OSes (may it be GNU/Linux, xBSD, or whatever).
>>>
>>> take a look at Cyrus, it is _very_ scalable, and includes replication and
>>> clustering capabilities. It's routinely used by universities and other
>>> larger
>>> organizations.
>>
>> Cyrus is a nice player in the field (still run it myself on some hosts),
>> but it has some major drawbacks:
>>
>> - - proprietary mail storage mechanism (compared to MailDir/mbox et al.)
>
> three things here
>
> 1. Cyrus is open source and everything is documented, this is not normally
> what
> 'proprietary' is used to mean. it does have a different on-disk format than
> MailDir or mbox
By proprietary he means: only cyrus uses it!
Dovecot has its own *proprietary* formats too:
http://wiki.dovecot.org/MailboxFormat
>
> 2. if you are accessing it via IMAP/POP, why should you care what mechanism it
> uses?
As an admin, if I'm going to stay to cyrus, I shouldn't care. As an
user: I should not note the difference if you are using whatever imap
server, I would just want my mail!
>
> 3. the storage mechanism is very similar to MailDir (one file per message,
> folders are directories on the filesystem, etc) and mostly differs in how the
> metadata is handled. I frequently write scripts to analyse/parse e-mail in an
> archive folder so while it's 'proprietary', it's fully documented
>
>> - - slower than Dovecot, e.g.
I think they are pretty much the same, maybe, dovecot a little faster
(but, definitely, I find dovecot more security-oriented), or maybe
Cyrus a little faster..... not sure.
>
> I can't speak to this, but does Dovecot implement the clustering and
> replication
> features that Cyrus does that lets it scale across many machines?
http://cyrusimap.web.cmu.edu/twiki/bin/view/Cyrus/CyrusCluster
Nothing new, except, maybe, the replication thing, Cyrus suggest the
use of Perdition (which can be very problematic, specially with
SSL/TLS related issues).
Off course, I have to add: at least it have part of its documentation
dedicated to cluster configuration.
http://cyrusimap.web.cmu.edu/imapd/install-replication.html
(Replication) Looks like it is not ready for "load balancing", which
is bad (and, at last, this comes back "on-topic"). It is only for HA,
not load balancing.
Furthermore, Dovecot has this:
http://wiki.dovecot.org/PasswordDatabase/ExtraFields/Proxy
Which replaces perdition.
And, this:
http://wiki.dovecot.org/MailLocation/SharedDisk
Which clearly states that you can build clusters with Dovecot, by
sharing mailstores. Also, I would have to say that: you can build the
"other" kind of clusters, where you have different users on different
servers (ala yahoo, or hotmail), with the proxying capabilites (or on
Cyrus by using perdition).
>
>> - - compared to other pop/imap servers, it does not implement RFCs as good
>> as others (Dovecot is very good here, too)
>
> I would be interested in hearing where Cyrus is behind, this is the first time
> I've heard this and I've been considering Cyrus as one of the best IMAP
> implementations available.
There was a comparison on this, I read it some time ago (>1 year,
can't find it right now), they compared several IMAP servers on the
status and quality of the RFCs implementation, and Dovecot had it all.
>
>
> I'll also point out that fastmail.fm, which is a major 'cloud' mail provider
> (even though they've been in business longer than the term has existed) uses
> Cyrus and is active in it's development.
fastmail works on cyrus development? no wonder they use it, I would be
worried if they didn't used it!
Other thoughts:
I believe that both Cyrus and Dovecot are good products (I had a
really hard time making a decision between them both three years ago),
both have SASL implementations, both have good performance, but what
drove me to Dovecot was:
1. Easier to configure (in *my* opinion).
2. Security-oriented design.
3. More complete standards implementation
I hope this helps,
Ildefonso Camargo
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