Date: Thu, 14 Oct 2004 20:58:45 +0300 From: "Bigbrother" <bigbrother@bonbon.net> To: <freebsd-questions@freebsd.org> Subject: NFS data integrity failure Message-ID: <200410141758.i9EHwDMm000439@bigb3server.bbcluster.gr>
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Dear all, I have noticed a very strange NFS problem between two FreeBSD machines running both 4.10-Release-p2. ---------Short description: NFS copy transfers from A to B (A controls the transfer, e.g. he "gets" data ) produce (always!!) CRC errors and MD5 mismatch between (some) original files and copies (6-7 files out of 90) NFS copy transfers from A to B (B controls the transfer, e.g. he "puts" data) make exact copies EVERYTIME!!! NFS mounts have been tried with TCP, UDP, read/write of 8K or 16K,nfsv2, nfsv3 --------Long description: MachineA mount machineB:/disk and copies 1.2 GB of data from machineB:/disk to local disc (gets data) (almost 90 files of 15MB each). After, the transfer I compare the CRC of every copied file with the original CRC and some files produce different CRCs. If I copy again the failed file the CRC is correct. Of course this means that I should manually verify every time that copies are 100% the same with original, which is a bit waste of time. MachineB mounts machineA:/disk and puts 1.2 GB of data from its disk to the machineA dick. A CRC check performed on the copied files show that everything is correct. (always!) Other tests: MachineB mounts machineA:/disk and gets 1.2GB of data from machineA:/disk. Everything is correct MachineA mounts machineB:/disk and puts data on machineB. Some files have CRC errors!! Every time the files that are damaged are different. NFS mounts are done with the same parameters every time Different combinations of NFS mount parameters have been tried and every time the results are the same. MachineA: CPU: AMD Athlon(tm) Processor (807.19-MHz 686-class CPU) real memory = 134135808 (130992K bytes) Network card: Realtec 8139 MachineB: CPU: Intel Pentium III (731.47-MHz 686-class CPU) real memory = 536870912 (524288K bytes) Network card: 3Com 3c905C-TX Fast Etherlink XL Both machines are not in any load. No errors reported by syslog!!! -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- What is happening? How can I find out what is causing this? Is it possible that realtek card causes such behavior? On the other hand why some transfers succeed every time? I am not in the situation of buying another network card for my home machine, so if you have any suggestion of how to resolve this problem let me know...Have you got any similar situations? How did you solved them? I have searched the net and have not found any useful information about it. Thank you a lot in advance!! --- Give a man fire, and he'll be warm for a day; set a man on fire, and he'll be warm for the rest of his life
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