From owner-freebsd-fs@freebsd.org Wed Apr 4 19:14:26 2018 Return-Path: Delivered-To: freebsd-fs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 718E7F6EAF7 for ; Wed, 4 Apr 2018 19:14:26 +0000 (UTC) (envelope-from mad@madpilot.net) Received: from mail.madpilot.net (grunt.madpilot.net [78.47.145.38]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 0BF916EBFE for ; Wed, 4 Apr 2018 19:14:25 +0000 (UTC) (envelope-from mad@madpilot.net) Received: from mail (mail [192.168.254.3]) by mail.madpilot.net (Postfix) with ESMTP id 40Gb3m6PCmzZr4; Wed, 4 Apr 2018 21:04:20 +0200 (CEST) Received: from mail.madpilot.net ([192.168.254.3]) by mail (mail.madpilot.net [192.168.254.3]) (amavisd-new, port 10024) with ESMTP id Qj7lXimlZ47g; Wed, 4 Apr 2018 21:04:09 +0200 (CEST) Received: from tommy.madpilot.net (host190-122-dynamic.6-87-r.retail.telecomitalia.it [87.6.122.190]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.madpilot.net (Postfix) with ESMTPSA; Wed, 4 Apr 2018 21:04:09 +0200 (CEST) Subject: Re: Linux NFS client and FreeBSD server strangeness To: Mike Tancsa , "freebsd-fs@freebsd.org" References: <369fab06-6213-ba87-cc66-c9829e8a76a0@sentex.net> From: Guido Falsi Message-ID: <2019ee5a-5b2b-853d-98c5-a365940d93b5@madpilot.net> Date: Wed, 4 Apr 2018 21:04:09 +0200 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <369fab06-6213-ba87-cc66-c9829e8a76a0@sentex.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 04 Apr 2018 19:14:26 -0000 On 04/04/18 20:27, Mike Tancsa wrote: > Not sure where the tweaking needs to happen, but I am getting strange > behaviour between a Linux nfs client and FreeBSD RELENG_11 NFS server. > > The FreeBSD server starts with > > > nfs_client_enable="YES" > nfs_server_enable="YES" > > > rpcbind_enable="YES" > rpc_lockd_enable="YES" > rpc_statd_enable="YES" > nfs_server_flags="-u -t -n 16" > > and on the Linux client I have been trying various options to no avail. > The mount works, but on a straight up write to the FreeBSD server, > everything is very bursty. I noticed this (I think) a few months ago > where Linux dumps across an nfs mount seemed to take a lot longer and > were getting very bursty. > > It seems if there are a mixture of reads and writes, everything is > pretty fast. But if a client is just writing to the server, something, > somewhere is blocking. Doing something simple like > ls -l /nfsmount > from the client "wakes" up the server/client so that write stream can > keep going. Otherwise, it will do a big blast of writes and then several > seconds of pausing on the dump. Looks like you're using ZFS. Most probably that's the cause. NFS requires frequent syncs, and ZFS respects those, becoming slow, being unable to take advantage of the ZIL. you can find more details here: https://wiki.freebsd.org/ZFSTuningGuide in the NFS tuning section. If you're not using ZFS I don't have an idea right away what your problem could be. -- Guido Falsi