From: "Dawid Pawlata" Subject: Re: [NFS] Strange NFS behaviour Date: Tue, 18 Dec 2007 16:37:27 +0100 (CET) Message-ID: <1351.194.237.142.6.1197992247.squirrel@www.active24.pl> Reply-To: dawid-g7DOKF3l0ejVItvQsEIGlw@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII To: linux-nfs@vger.kernel.org Return-path: Received: from kurier1.active24.pl ([195.78.67.20]:33706 "EHLO kurier1.active24.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757035AbXLRPha (ORCPT ); Tue, 18 Dec 2007 10:37:30 -0500 Received: from localhost (localhost [127.0.0.1]) by kurier1.active24.pl (Postfix) with ESMTP id 5293C54090 for ; Tue, 18 Dec 2007 16:37:29 +0100 (CET) Received: from www.active24.pl (unknown [192.168.111.78]) by kurier1.active24.pl (Postfix) with ESMTP id B02FD5408A for ; Tue, 18 Dec 2007 16:37:27 +0100 (CET) Sender: linux-nfs-owner@vger.kernel.org List-ID: Hi! In case that someone has similar problem I just want to say that this was NFS server side problem. The NIS service was sometimes unavailable and NFS server could not contact it. BR Dawid > Hi! > > It looks like there is a way to workaround this problem. One can simply > list the mounted directory before the TCP connection times out (which > takes place after 4 minutes by default). Simple ls command on the mounted > path every minute should make the problem gone. > > I still wonder what is the real cause of the problem and is it the client > or the server that is buggy. This problem is really annoying. > > I have been trying to use settings described in "Technical Report: Using > the Linux NFS Client with Network Appliance Storage" > (www.netapp.com/tech_library/ftp/3183.pdf) with no success. > > Best Regards > Dawid > >> Hi! >> >> I have an NFS resource mounted from a dedicated machine NetApp FAS3050 >> using NFS v3 over TCP. >> The NFS client works on SuSe Linux Enterprise Server 10 SP1, kernel ver >> 2.6.16.46-0.14-smp. >> >> When the NFS is idle for few hours, the NFS resources sometimes become >> inaccessible. Every process accessing such resource hangs. >> >> I have sniffed the NFS connection and found an interesting behaviour of >> the NFS client/server: >> >> time src dest proto port numbers content >> >> 16692.276474 client server TCP 1023 > 2049 [SYN] >> 16692.277171 server client TCP 2049 > 1023 [SYN, ACK] >> 16692.277189 client server TCP 1023 > 2049 [ACK] >> 16692.277197 client server NFS 1023 > 2049 V3 ACCESS Call, >> FH:0x30ed5a16 >> 16692.378613 server client TCP 2049 > 1023 [ACK] >> 16701.285748 server client TCP 2049 > 1023 [FIN, ACK] >> 16701.285764 client server TCP 1023 > 2049 [FIN, ACK] >> 16701.285790 client server TCP 1022 > 2049 [SYN] >> 16701.286497 server client TCP 2049 > 1022 [SYN, ACK] >> 16701.286506 client server TCP 1022 > 2049 [ACK] >> 16701.286508 server client TCP 2049 > 1023 [ACK] >> 16701.286512 client server TCP 1022 > 2049 V3 ACCESS Call, >> FH:0x30ed5a16 >> 16701.287247 server client TCP 2049 > 1022 [FIN, ACK] >> 16701.287257 client server TCP 1022 > 2049 [FIN, ACK] >> 16701.287271 client server TCP 1021 > 2049 [SYN] >> >> >> Since there was no active TCP connection to the NFS server, it has been >> established. Then, an NFS ACCESS command was sent to the server. The >> server did not answer the NFS query, but initialised the TCP connection >> close instead. >> >> After receiving [FIN, ACK] the client reconnected immediately, but this >> time on port 1002 (since 1023 is still in use at this point). Again, the >> server closed the TCP connection and another attempt was made on a new >> port number. >> >> This is not on the log, but the NFS client keeps repeating this on each >> of >> the port numbers in range <1023,664>. When port number 664 is reached, >> the >> NFS server stops answering the TCP SYN packets. >> >> This started to happen after upgrading linux from SuSe Linux 10.1 >> 2.6.16.21-0.25-smp. Another thing is that there are also VxWorks clients >> using that NFS server which work fine. >> >> Do you have any idea of what is the reason for such behavior? >> >> Thanks in advance. >> >> Regards, >> Dawid Pawlata >> >> - >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > > - > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- pozdro Dawid