[Dovecot] nfs director

[Noel Butler]

On Fri, 2010-08-27 at 08:54 +1000, Edward avanti wrote:

> Halo,
> Please can you explain why this is advantage over a hardware load balancer.


it is no advantage over a dedicated hardware solution, but director does
not do the exact same thing.


> I fail to see advantage if anything it add in more point of failure, with


i agree with this and it is why we dont use it

we use dovecots deliver with postfix and have noticed no problems, not
to say there was none, but if so, we dont notice it.
postfix looks up the user, it determines if it accepts the mail, if it
does, it queues it for mailscanner to do its stuff, then gives it back
to postfix, which is then told to give it to dovecots deliver, it makes
no sense to me that it should then be sent to another machine just to be
stored on a remote file server, the same remote file server the initial
server assigned that conenction by a true load balancer has mounted and
would store it to as well.... would be miuch easier to have deliver
ignore the index file by an option, eliminating the corruption risks to
the index file and just storing the darm thing. or am i only one who
thinks mail systems do not need to be complex to run faultlessly, I
think those who feel the need to make it very complex are not only
looking for trouble, but further trying to justify their position to
their employer that they are indispensable.



> 
> if director service assign 60K user to each front end,  how it handle if 5K
> simultaneous user login, but all 5K happen to be assign to that one machine,


that would be rare, but, technically speaking, if you are that large in
user numbers, it is a possible scenario


> Is it really worth it? Do we really need this, or just let foundry switch
> handle it as it does now.
> We also have 24 front end SMTP server, these deliver mail to netapp filer,
> all 24 plus 8 pop3 server and 2 webmail imap server all mount /vmail, so all
> access same maildir. it seem work very effective thus far and for many many


Sounds similar setup to us, smtp, pop3 and webmail all
mounting /var/vmail/ on a FAS2050,  I've asked if it can avoid touching
the index files before (see a thread as recent as a few weeks back),
Timo is just not interested, to much work apparently for so little users
(although I never in all hte years ive been on this list, ever seen a
poll taken/question asked to users - about it, plus, well, every single
dovecot user  is on this list, right? <sarcasm>  anyway, mostly I guess
although it has risks, it seems to work for everyone who uses NFS anyway
and has done for very many years :) , maybe one day when Timo is so
bored and cant think of anything to add, he will give us an option, or a
dedicated deliver binary separate to normal deliver that does this)

/rant ( but its nice to know im not the only one here who feels this
way)
Cheers

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