Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-ie0-f174.google.com ([209.85.223.174]:46656 "EHLO mail-ie0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753990AbaDWVEc (ORCPT ); Wed, 23 Apr 2014 17:04:32 -0400 Received: by mail-ie0-f174.google.com with SMTP id rp18so1522513iec.33 for ; Wed, 23 Apr 2014 14:04:31 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20140423204405.GB16168@us.ibm.com> References: <20140423202401.GA16168@us.ibm.com> <20140423204405.GB16168@us.ibm.com> Date: Wed, 23 Apr 2014 23:04:31 +0200 Message-ID: Subject: Re: Tuning Linux NFSv4 for high latency connections? From: Cedric Blancher To: Cedric Blancher , Linux NFS Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On 23 April 2014 22:44, Malahal Naineni wrote: > Cedric Blancher [cedric.blancher@gmail.com] wrote: >> On 23 April 2014 22:24, Malahal Naineni wrote: >> > Cedric Blancher [cedric.blancher@gmail.com] wrote: >> >> Are there any options to improve the Linux NFSv4 performance over a >> >> high latency connection? >> >> >> >> We currently use Solaris/Illumos as NFSv4 server and client over a >> >> cross continental Internet connection. Latency is terrible (~220ms) >> >> but the counter this by running work in parallel so the latency is >> >> mostly mitigated. >> >> >> >> We now wish to migrate (short: Away from Oracle because support is >> >> basically unbearable) to Linux (tested SuSE 13.1 and current Fedora) >> >> and build times are 17 times (!!!) SLOWER than on Solaris/Illumos. >> >> >> >> Are there any tunables besides actimeo=300? >> > >> > rsize and wsize may help! You need to figure out if the read is the >> > issue or the write before you dig further. >> >> I already tried to tune rsize/wsize, making them both smaller or the >> maximum of 1048576 bytes, with no effect. >> >> One possible theory is that maybe something in Linux doesn't allow >> multiple requests to be issued in parallel and waits for each request >> to be completed before issuing the next one? > > Linux NFS client can issue I/Os in parallel. Should be limited by number > of RPC slots though. What controls the number of RPC slots? is there a tunable? Is there something to monitor the usage? Ced -- Cedric Blancher Institute Pasteur