Return-Path: Received: from mga05.intel.com ([192.55.52.43]:16046 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750796AbcIIFgL (ORCPT ); Fri, 9 Sep 2016 01:36:11 -0400 From: "Fu, Yong" To: "linux-nfs@vger.kernel.org" Subject: NFS write throughput not constant Date: Fri, 9 Sep 2016 05:34:54 +0000 Message-ID: Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: Hi, I have some test on 10Gbe against NFS-based storage recently, and found the throughput of writing was not constant, the performance of writing drop down periodically. My nfs client(version 3 and version 4 all tried) resident CentOS 6.6(2.6.32-504.el6.x86_64), NFS server is OpenMediaVault(5 ssd with stripe) On a single mount point(or single nfs client), the avg throughput only can reach 430 MB/s, and two nfs clients aggregation can reach 700 MB/s, I can see there is periodical drop of network traffic graph both client and server side, and I am sure it's a nfs issue by lots of other tests. I also found the nfs client commit procedure happened at the time that writing performance also dropped, and I have read B7 section(http://nfs.sourceforge.net) and think the relationship between them, but no many ideas, can someone help me pinpoint the root cause of this issue?