Date: Sat, 25 Jan 2014 21:25:30 -0500 (EST) From: wollman@freebsd.org To: rmacklem@uoguelph.ca Cc: freebsd-fs@freebsd.org, freebsd-net@freebsd.org Subject: Re: Terrible NFS performance under 9.2-RELEASE? Message-ID: <201401260225.s0Q2PUp1045129@hergotha.csail.mit.edu> In-Reply-To: <278396201.16318356.1390701347722.JavaMail.root@uoguelph.ca> References: <CABXB=RSGhshBe3CWDiQcis4fYYHqRbyQr70QiXM1nLMTSyCQvQ@mail.gmail.com>
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In article <278396201.16318356.1390701347722.JavaMail.root@uoguelph.ca>, Rick Macklem writes: >Well, when I get home in April, I'll try the fairly recent Linux client >I have at home and see what it does. Not sure what trick they could use >to avoid the read before write for partial pages. (I suppose I can >look at their sources, but that could be pretty scary;-) For what it's worth, our performance for large-block 100%-read workloads is also not what it could (or ought to) be. Between two 20G-attached servers, I can get about 12 Gbit/s with three parallel TCP connections. (Multiple connections are required to trick the lagg hash into balancing the load across both 10G links, because the hash function used for load-balancing uses the source and destination ports.) On the same pair of servers, "dd if=/mnt/test bs=1024k" runs at about 3 Gbit/s, whereas reading from the local filesystem goes anywhere from 1.5 to 3 G*byte*/s (i.e., eight times faster) with much higher CPU utilization. Luckily, most of our users are only connected at 1G so they don't notice. I'm going to lose my test server soon (it has to go into production shortly), so I'm not really able to work on this. I'll have another test server soon (old hardware being replaced by the new server) and hope to be able to try out the new code that's going to be in 10.1, with the expectation of upgrading to 10.x over summer break. -GAWollman
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