Corrupted data on write to Windows 2003 Server
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Corrupted data on write to Windows 2003 Server
by Danny Sung-2
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When copying a file from linux to windows, I noticed corrupted data
whenever my data size is larger than about 100-200MB. I ran a few tests, using 'dd', writing a 1GB file with varying block sizes (1, 10, 50, 100, and 200 megs). Each one reported a different md5 when reading back. Only the 200 MB block size was successful, but it may have been a fluke... I need to run the test a few more times. The actual number of bytes in the destination file is correct. But running 'cmp' afterwards, I discovered that the destination ends up being 0 padded after a certain point. The exact spot seems to wander, but it appears to be around the 800-900MB mark for these files. I don't get any error messages or anything from the actual 'dd' command. The only message I get is a kernel message saying: "CIFS VFS: No writable handles for inode", which I suppose explains it all. But it'd be nice if the user commands reported some sort of failure. I don't suppose there are any mount options I can give to cifs to make it do more checking or retries or anything? Or how do I actually prevent the "no writable handles" problem? Of course, if I use rsync, that seems to get around the problem. But it seems kind dumb to have to do that for mounted filesystems. =P Linux system: Fedora Core 5 Linux aeolus.eng.lantronix.com 2.6.18-1.2200.fc5smp #1 SMP Sat Oct 14 17:15:35 EDT 2006 i686 i686 i386 GNU/Linux Windows System: Windows Server 2003 R2 Standard w/ SP1 mount options: cifs (rw,mand) I don't think this uses samba since cifs is a kernel module, but just in case, my samba version is: 3.0.23c Thanks for any assistance, Danny --- Please ignore the following disclaimer, not the message. =) ********************************************************************** This e-mail is the property of Lantronix. It is intended only for the person or entity to which it is addressed and may contain information that is privileged, confidential, or otherwise protected from disclosure. Distribution or copying of this e-mail, or the information contained herein, to anyone other than the intended recipient is prohibited. _______________________________________________ linux-cifs-client mailing list linux-cifs-client@... https://lists.samba.org/mailman/listinfo/linux-cifs-client |
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Re: Corrupted data on write to Windows 2003 Server
by Shirish S Pargaonkar
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linux-cifs-client-bounces+shirishp=us.ibm.com@... wrote on 12/08/2006 01:24:24 PM: |
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Re: Corrupted data on write to Windows 2003 Server
by Danny Sung-2
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Thanks so much! That solved the problem. Curiously, I also seem to get
better performance! 7 MB/sec rather than 5 MB/s. Perhaps I should run the test again... it's possible the system was loaded with backups the first time. Shirish S Pargaonkar wrote: > linux-cifs-client-bounces+shirishp=us.ibm.com@... wrote on > 12/08/2006 01:24:24 PM: > > > When copying a file from linux to windows, I noticed corrupted data > > whenever my data size is larger than about 100-200MB. I ran a few > > tests, using 'dd', writing a 1GB file with varying block sizes (1, 10, > > 50, 100, and 200 megs). Each one reported a different md5 when reading > > back. Only the 200 MB block size was successful, but it may have been a > > fluke... I need to run the test a few more times. > > > > The actual number of bytes in the destination file is correct. But > > running 'cmp' afterwards, I discovered that the destination ends up > > being 0 padded after a certain point. The exact spot seems to wander, > > but it appears to be around the 800-900MB mark for these files. > > > > I don't get any error messages or anything from the actual 'dd' command. > > The only message I get is a kernel message saying: "CIFS VFS: No > > writable handles for inode", which I suppose explains it all. But it'd > > be nice if the user commands reported some sort of failure. > > > > I don't suppose there are any mount options I can give to cifs to make > > it do more checking or retries or anything? Or how do I actually > > prevent the "no writable handles" problem? > > > > Of course, if I use rsync, that seems to get around the problem. But it > > seems kind dumb to have to do that for mounted filesystems. =P > > > > > > > > Linux system: Fedora Core 5 > > Linux aeolus.eng.lantronix.com 2.6.18-1.2200.fc5smp #1 SMP Sat Oct 14 > > 17:15:35 EDT 2006 i686 i686 i386 GNU/Linux > > > > > > Windows System: Windows Server 2003 R2 Standard w/ SP1 > > > > mount options: cifs (rw,mand) > > > > I don't think this uses samba since cifs is a kernel module, but just in > > case, my samba version is: 3.0.23c > > > > Thanks for any assistance, > > Danny > > > > --- > > Please ignore the following disclaimer, not the message. =) > > ********************************************************************** > > This e-mail is the property of Lantronix. It is intended only for > > the person or entity to which it is addressed and may contain > > information that is privileged, confidential, or otherwise protected > > from disclosure. Distribution or copying of this e-mail, or the > > information contained herein, to anyone other than the intended > > recipient is prohibited. > > > > _______________________________________________ > > linux-cifs-client mailing list > > linux-cifs-client@... > > https://lists.samba.org/mailman/listinfo/linux-cifs-client > > Danny, > > We have seen this problem and are working on it. Sizes of the source > and destination files are same but > md5sum would report different values. I have seen this problem with > large files like 500MB+. > I have seen some (page) ranges in destination file filled with NUL bytes. > But we have observed this problem only with copying files to Windows > server and not with Samba server. > > As a work-around, you may want to use option forcedirectio during mounts. > > Regards, > > Shirish S. Pargaonkar > _______________________________________________ linux-cifs-client mailing list linux-cifs-client@... https://lists.samba.org/mailman/listinfo/linux-cifs-client |
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Re: Corrupted data on write to Windows 2003 Server
by Danny Sung-2
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Just giving you an update. forcedirectio seems to be a lot more
reliable than not having the option. However, for a particularly large file (eg. 6GB) it aborts with a message saying "Host down". Shirish S Pargaonkar wrote: > Danny, > > We have seen this problem and are working on it. Sizes of the source > and destination files are same but > md5sum would report different values. I have seen this problem with > large files like 500MB+. > I have seen some (page) ranges in destination file filled with NUL bytes. > But we have observed this problem only with copying files to Windows > server and not with Samba server. > > As a work-around, you may want to use option forcedirectio during mounts. > > Regards, > > Shirish S. Pargaonkar > This e-mail is the property of Lantronix. It is intended only for the person or entity to which it is addressed and may contain information that is privileged, confidential, or otherwise protected from disclosure. Distribution or copying of this e-mail, or the information contained herein, to anyone other than the intended recipient is prohibited. _______________________________________________ linux-cifs-client mailing list linux-cifs-client@... https://lists.samba.org/mailman/listinfo/linux-cifs-client |
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Re: Corrupted data on write to Windows 2003 Server
by Shirish S Pargaonkar
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linux-cifs-client-bounces+shirishp=us.ibm.com@... wrote on 12/08/2006 01:24:24 PM: |
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