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Samba mount and access large 2GB+ files from share or NAS device

Q. I’m using NAS server share to make a backup of my webserver. However samba is not allowing me to backup of large files (2GB+).

My Samba share mount command is as follows:
smbmount //nas1.domain.com/sharename /datanas -o username=LOGINNAME,password=LOGINPASSWORD

Now if I copy file called /var/log/httpd/access.log (which is 3.5 GB file):
cp /var/log/httpd/access.log /datanas

I get ab error - file size limit exceeded

How do I solve this problem and copy large files to NAS samba share?

A. Linux kernel use smbfs.ko/smbfs.o module and it does not support file sizes greater than 2 GB. This is well known problem.

Mount your NAS samba share with lfs (large file system) option. General syntax is as follows:
smbmount //Hostname/Username /local/mountpoint -o username=username,password=password,lfs

For example:
# smbmount //nas1.domain.com/sharename /datanas -o username=LOGINNAME,password=LOGINPASSWORD,lfs


  • //nas1.domain.com/sharename : Server and Share name
  • /datanas : Local mount point
  • -o username=LOGINNAME,password=LOGINPASSWORD,lfs : Specify login, password and lfs options

Now you should be able to copy large files w/o a problem.

{ 5 comments… add one }
  • gary June 9, 2007, 10:39 am

    Thank you for adding this information. It proved very helpful.

  • Leonard Lilla September 10, 2007, 1:40 am


    Well, I had been looking for this a long time. I don’t know why I never landed on this site before. But I am here and thank you for this post. Saves me a lot of trouble!


  • John January 27, 2008, 10:42 pm

    Did you format the drive using the NTFS format? it sounds to me the drive is formatted as FAT32, which does not allow for files larger than 2GB

  • DanD March 3, 2008, 3:22 pm

    FAT32 allows files larger than 2GB, up to almost 4GB

    “You cannot create a file larger than (2^32)-1 bytes (this is one byte less than 4 GB) on a FAT32 partition.”


    also http://en.wikipedia.org/wiki/Fat32#FAT32

  • nisarg March 4, 2008, 6:49 pm

    Hi, thanks!
    Thats been very useful.
    I was stuck at 2GB trying to rescue 60gb disk, writing to an NFTS partition mounted via SMBMOUNT.
    Just one question. With this lfs option – is there any limits at all? i hope not

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