Date: Fri, 28 Jul 2000 21:04:43 +0100 From: David Malone <dwmalone@maths.tcd.ie> To: mi@aldan.algebra.com Cc: stable@freebsd.org Subject: Re: rdist and pam Message-ID: <200007282104.aa49997@salmon.maths.tcd.ie> In-Reply-To: Your message of "Fri, 28 Jul 2000 09:48:26 EDT." <200007281348.JAA99713@misha.privatelabs.com>
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> What you should, probably, use is rdist6 over ssh with ssh compression > disabled. It is the compression, not the encryption that kills the > throughput on fast networks. Having the traffic encrypted is better > anyway for the long run, although you can build ssh with the cypher > ``none'' available and use it... This is what we're doing at the moment and the authentication side works fine. Even without compression we find it is much slower than using rsh, and as far as we can tell, this is because rdist does a lot of: Tell me about file blah waits for response Tell me about file wibble waits for response . . . and ssh seems to add quite alot to the RTT for these small transactions, so rdist spends most of it's time waiting. We've changed this to do: Tell me about file blah Tell me about file wibble . . Now process the responses It's much like the SMTP pipelining changes. It's nice 'cos it needs no protocol changes, and just requires that you avoid deadlocks by checking for data to be read before writing. Out nightly rdisting jobs have gone from about 5 hours down to a bit over 1 (over ssh). I think you also see significant gains when using rsh, but I haven't done any measurements yet. I'm trying to write this up.... David. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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