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Re: [SLUG] Opinions sought: Exim vs Sendmail
- To: slug@xxxxxxxxxxx
- Subject: Re: [SLUG] Opinions sought: Exim vs Sendmail
- From: Del <del@xxxxxxxxxxxx>
- Date: Sun, 29 Jun 2003 15:44:18 +1000
- User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20030225
On 24 Jun, Oscar Plameras wrote:
True, email services is dns service intensive. It demands both forward and
reverse lookup services. So, when MTA requires DNS services it is
serviced by named in the same box. First, the catch is, named is less
We had some problems at work with system lockups during periods of high
email delivery load, due to the cost of the DNS lookups - on Linux. If
a few hundred emails arivved for delivery at approximately the same
time, it brought the machine to its knees, and took a long long time to
recover, as more email arrived in the meantime.
As I roughly recall from one of our sysadmin people's explanation,
Solaris apparently doesn't suffer the same way since it caches in memory
the DNS lookup results.
Seems like an obvious thing to do. Any hint that the appropriate Linux
DNS component might be improved in the same way?
/usr/sbin/nscd - name service cache daemon
Nscd is a daemon that provides a cache for the most common name service
requests. The default configuration file, /etc/nscd.conf, determines
the behavior of the cache daemon. See nscd.conf(5).