Return-Path: linux-nfs-owner@vger.kernel.org Received: from aserp1040.oracle.com ([141.146.126.69]:46630 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752558AbaAPPzO convert rfc822-to-8bit (ORCPT ); Thu, 16 Jan 2014 10:55:14 -0500 Content-Type: text/plain; charset=windows-1252 Mime-Version: 1.0 (Mac OS X Mail 7.1 \(1827\)) Subject: Re: nfs attribute cache question From: Chuck Lever In-Reply-To: Date: Thu, 16 Jan 2014 10:55:10 -0500 Cc: Linux NFS Mailing List Message-Id: References: To: ranjith ruban Sender: linux-nfs-owner@vger.kernel.org List-ID: On Jan 16, 2014, at 6:31 AM, ranjith ruban wrote: > Hello > > I had set nfs mount actiomeo option for 300 seconds for a share. The > client is an openvz server with container filesystems in nfs . Server > is netapp. > > While going through the tcpdump i see below > > 125 2014-01-15 16:06:01.770522 10.X.0.X 10.X.0.X NFS > 190 V3 GETATTR Call (Reply In 126), FH: 0x496fe5c5 > 126 2014-01-15 16:06:01.770637 10.X.0.X 10.X.0.X NFS > 182 V3 GETATTR Reply (Call In 125) Regular File mode: 0644 uid: > 0 gid: 0 > > this call returns file id 2691421 > > find /vz/private/X/ -inum 2691421 -exec ls -l {} \; > -rw-r--r-- 1 root root 1128 Jul 14 2011 /vz/private/X/fs/root/etc/passwd > > Now after a minute i do see the same call again to same file handle. > > 294 2014-01-15 16:07:01.771152 10.X.0.X 10.X.0.X NFS > 190 V3 GETATTR Call (Reply In 295), FH: 0x496fe5c5 > 295 2014-01-15 16:07:01.771261 10.X.0.X 10.X.0.X NFS > 182 V3 GETATTR Reply (Call In 294) Regular File mode: 0644 uid: 0 > gid: 0 > > mount options > # 10.X.0.X:/vol/vz2/private on /vz/private type nfs > (rw,noatime,nodiratime,soft,timeo=60,nfsvers=3,retrans=2,rsize=8192,wsize=8192,actimeo=300,addr=10.X.0.X) > > why does this happens with actimeo=300 . The second call in 1 minute > should be answered from cache is it ?. Can some tuning be done to > reduce this?. With NFSv3, open(2) on the client results in an on-the-wire GETATTR, independent of the freshness of the file?s attribute cache. See ?DATA AND METADATA COHERENCE? in the nfs(5) man page. -- Chuck Lever chuck[dot]lever[at]oracle[dot]com