Hi all, Thanks Peter, for you kind reply - some setup you have there... sounds very nice indeed...:-) ! - If i have a lower budget, can this then be achieved without the loadbalancers and still have same redundancy/flexibility (using e.g. "DNS RR"/"MX with equal value") - if so what is for/against/preferred ?: DNS RR: so just have like load-sharing (mail1->postfix1, mail2->postfix2, mail3->postfix1, etc.). But if one postfix servers goes down, will all DNS replies then be only for alive-postfix - or will there also be dead-postfix replies that needs to timeout, before it retries (and for how many times?) and potentially end up dropping the mail if it is so unlucky to get replies for dead-postfix on all retries ? "MX with equal value": is this handling differently? does a request load all MX records for the domain, and then sort them by value and then alphabetically, ending up with: if one postfix is down it will automatically try the next one in the sorted list...?
Thanks in advance :-) ! ~maymann Den 27. dec. 2011 10.29 skrev Peter Sørensen <mas...@sdu.dk>: > Hi Michael,**** > > ** ** > > We use a solution with 2 loadbalancers in front of 3+ postfix servers**** > > All MX records ( for around 100 domains ) are directed to the same address > – the **** > > address of the loadbalancers. Based on statistics for each server the**** > > mail is redirected to one of the 3-6 postfix servers we have running.**** > > Statistics for each server is written to Our Mysql Backend cluster where > all postfix**** > > related files are located **** > > ** ** > > As long as just one postfix server is running - mail is in function. We > are able to add**** > > more servers on the fly depending on load.**** > > ** ** > > Best regards**** > > ** ** > > ** ** > > Peter Sørensen/Univ.Of.South.Denmark/email:mas...@sdu.dk **** > > * * > > *Fra:* owner-postfix-us...@postfix.org [mailto: > owner-postfix-us...@postfix.org] *På vegne af *Michael Maymann > *Sendt:* 27. december 2011 08:47 > *Til:* Postfix users > *Emne:* Re: Loadbalancing+failover solution**** > > ** ** > > Hi All, > Wietse: thanks for your replies - and sorry for not really knowing what > I'm asking...:-) > I guess my question is regarding receiving mail to PostFix: Linux > servers->PostFix. > is "DNS RoundRobin" or "MX record with equal value" preferred > > > thanks in advance :-) ! > > ~maymann**** > > 2011/12/23 Wietse Venema <wie...@porcupine.org>**** > > Wietse:**** > > > According to these: > > > > http://www.postfix.org/postconf.5.html#smtp_mx_address_limit > > http://www.postfix.org/postconf.5.html#smtp_mx_session_limit > > > > The Postfix SMTP client will try at least five IP addresses or two > > SMTP sessions, When it reaches either limit, Postfix will > > try another delivery later for several days. > > > > The retry schedule behaves as documented at: > > > > http://www.postfix.org/TUNING_README.html#hammer**** > > Michael Maymann:**** > > > Hi Wietse, > > > > thanks for your nice comments. > > > > I guess what you mention is valid for "my internal postfix relay > > server"->"ISP mailserver" - or am I mistaken ?**** > > What I write is valid for the Postfix SMTP client, whether > it sends mail to your ISP, or to your internal mail server. > > Wietse**** > > ** ** >
