Return-Path: Received: from neil.brown.name ([220.233.11.133]:34097 "EHLO neil.brown.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753753AbZB0LFN (ORCPT ); Fri, 27 Feb 2009 06:05:13 -0500 Received: from brown by neil.brown.name with local (Exim 4.69) (envelope-from ) id 1Ld0Wf-0004Z2-0p for linux-nfs@vger.kernel.org; Fri, 27 Feb 2009 22:05:05 +1100 From: Thorsten Meinl To: nfs@lists.sourceforge.net Date: Fri, 27 Feb 2009 12:04:05 +0100 Message-Id: <200902271204.05099.Thorsten.Meinl@uni-konstanz.de> Subject: [NFS] Write stalls over UDP and Gigabit Content-Type: text/plain; charset="us-ascii" Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Hi all, Ich have to computer connected via Gigabit Ethernet via just one switch. I did some experiments with dd from one computer to the other and got only rates of about 10MB/s. Looking further at it, it looks quite strange: for the first few seconds the transmission rate is at about 100MB/s which one would expect. Then it drops down to about 20MB/s and then to only a few megabytes. Using Wireshark I found out the following (this is a dump from the client that writes the 10GB file): 302 0.048432 192.168.224.75 192.168.224.206 IP Fragmented IP protocol (proto=UDP 0x11, off=5920) [Reassembled in #303] 303 0.048433 192.168.224.75 192.168.224.206 NFS V3 WRITE Call (Reply In 311), FH:0xdde80f28 Offset:2243969024 Len:8192 UNSTABLE 304 0.048515 192.168.224.206 192.168.224.75 NFS V3 WRITE Reply (Call In 254) Len:8192 UNSTABLE 305 0.048522 192.168.224.206 192.168.224.75 NFS V3 WRITE Reply (Call In 262) Len:8192 UNSTABLE 306 0.048527 192.168.224.206 192.168.224.75 NFS V3 WRITE Reply (Call In 268) Len:8192 UNSTABLE 307 0.048637 192.168.224.206 192.168.224.75 NFS V3 WRITE Reply (Call In 277) Len:8192 UNSTABLE 308 0.048762 192.168.224.206 192.168.224.75 NFS V3 WRITE Reply (Call In 283) Len:8192 UNSTABLE 309 0.048768 192.168.224.206 192.168.224.75 NFS V3 WRITE Reply (Call In 289) Len:8192 UNSTABLE 310 0.048887 192.168.224.206 192.168.224.75 NFS V3 WRITE Reply (Call In 295) Len:8192 UNSTABLE 311 0.048894 192.168.224.206 192.168.224.75 NFS V3 WRITE Reply (Call In 303) Len:8192 UNSTABLE 312 0.200814 192.168.224.75 192.168.224.206 IP Fragmented IP protocol (proto=UDP 0x11, off=0) [Reassembled in #317] 313 0.200822 192.168.224.75 192.168.224.206 IP Fragmented IP protocol (proto=UDP 0x11, off=1480) [Reassembled in #317] 314 0.200824 192.168.224.75 192.168.224.206 IP Fragmented IP protocol (proto=UDP 0x11, off=2960) [Reassembled in #317] There is a 0.2s delay between packet 311 and 312 and it is totally uncleat to me what could be the cause, as the reply for the last write call in 303 arrived in 311. So what is NFS waiting for (This situation occurs frequently and I assume this is the cause of the very low throughput). The server storage system and the network cannot be the problem because using sshfs I get rates of about 80MB/s and the bottleneck here is the CPU at the client side. I also tried TCP and there the rates are slightly better but still do not exceed ~20MB/s. Does anyone have an idea or any hints how I can debug this further? And yes, I already tried the various suggestions in the FAQs like increasing receive buffer sizes and such. Regards, Thorsten -- Thorsten Meinl room: Z815 Nycomed Chair for Bioinformatics fax: +49 (0)7531 88-5132 and Information Mining phone: +49 (0)7531 88-5016 Box 712, 78457 Konstanz, Germany ------------------------------------------------------------------------------ Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise -Strategies to boost innovation and cut costs with open source participation -Receive a $600 discount off the registration fee with the source code: SFAD http://p.sf.net/sfu/XcvMzF8H _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs _______________________________________________ Please note that nfs@lists.sourceforge.net is being discontinued. Please subscribe to linux-nfs@vger.kernel.org instead. http://vger.kernel.org/vger-lists.html#linux-nfs