Date: Mon, 13 Jul 2009 16:48:00 -0400 From: John Almberg <jalmberg@identry.com> To: Mel Flynn <mel.flynn+fbsd.questions@mailing.thruhere.net> Cc: freebsd-questions@freebsd.org Subject: Re: Should DNS be on same server as webserver? Message-ID: <3677DF1E-A610-4C33-A686-7A015C2D4597@identry.com> In-Reply-To: <200907131105.22889.mel.flynn%2Bfbsd.questions@mailing.thruhere.net> References: <8195A2D9-F7AC-49F8-969E-A13EDFA3C05A@identry.com> <200907131105.22889.mel.flynn%2Bfbsd.questions@mailing.thruhere.net>
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On Jul 13, 2009, at 3:05 PM, Mel Flynn wrote: > On Monday 13 July 2009 08:36:42 John Almberg wrote: >> The other day, a FreeBSD 'expert' told me that it is important to >> have the DNS server for a domain on the same server as the domain's >> web server. Supposedly, this saves doing tons of DNS look ups over >> the network. Instead, they are done locally. > > Bogus. A high-performance webserver should not be doing DNS > lookups, other > then application driven ones, like verification of email domains upon > registration. If having hostnames in the live logs is mandatory by > some weird > company policy or the webserver does not provide a configuration > setting to > turn this behavior off, then more performance is gained by having the > nameserver on the network gateway as the likeliness of cache hits and > especially negative cache hits is increased. As others have > mentioned, network > overhead is negligible. Human noticeable delays are caused by > upstream DNS > servers slowly or not at all responding when a client IP is being > resolved. > > Secondly, a named cache size depends on available memory. A high > performance > webserver uses plenty of that, so you wouldn't be able to grow the > named cache > to "almost caching the entire net" size, which you would be able to > on a > dedicated machine. Thanks for all the comments on this topic. Glad I put 'expert' in quotes. I had a feeling... -- John
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