load balancing among mail servers
in [Postfix]
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From: donovan jeffrey j on 16 Feb 2010 08:51 On Feb 16, 2010, at 8:09 AM, aa wrote: > Someone advised me to insert in the DNS zone a list of MX records > defined with the same level of priority so the DNS server will > choose one of them without invoking always the same mail server.... > It could be an idea, in my opinion, but I'd prefer a "less random" > solution and a more scientific one.... very easy for smtp relays. smtp1 smtp2 create a dns name smtp, and your system will round robin query for the next available server.
From: terry on 16 Feb 2010 13:35 Quoting Massimo Nuvoli <massimo(a)archivio.it>: > donovan jeffrey j ha scritto: >> >> On Feb 16, 2010, at 8:09 AM, aa wrote: >> >>> Someone advised me to insert in the DNS zone a list of MX records >>> defined with the same level of priority so the DNS server will choose >>> one of them without invoking always the same mail server.... >>> It could be an idea, in my opinion, but I'd prefer a "less random" >>> solution and a more scientific one.... >> very easy for smtp relays. >> smtp1 >> smtp2 >> create a dns name smtp, and your system will round robin query for the >> next available server. > > DNS round robin is bad, it works but is defective for real load > balancing. The client choose the IP to use, this is "random", and > after can use the same ip for a while... this is not random. > > The real solution is lvs or keepalived, the choice of the node is done > by the load balancer... A broken client that can't be bothered to check MX records isn't anybody's problem except the sender. In fact, just like spambots, broken clients that send to the wrong MX tend to end up on RBLs fairly quickly, making them even less of a problem. Terry
From: "James R. Marcus" on 16 Feb 2010 15:00
I did round robin. Unless your servers are really under a high load I think this is more then suitable. James On Feb 16, 2010, at 8:51 AM, donovan jeffrey j wrote: > > On Feb 16, 2010, at 8:09 AM, aa wrote: > >> Someone advised me to insert in the DNS zone a list of MX records >> defined with the same level of priority so the DNS server will >> choose one of them without invoking always the same mail server.... >> It could be an idea, in my opinion, but I'd prefer a "less random" >> solution and a more scientific one.... > > very easy for smtp relays. > > smtp1 > smtp2 > > > create a dns name smtp, and your system will round robin query for the > next available server. |