[kwlug-disc] backups capped at 2 gigs

John Van Ostrand john at netdirect.ca
Tue Jul 13 11:23:18 EDT 2010


----- Original Message -----
> I don't know how it works with ext2, ext3 or ext4 -- it seems to me to
> be the same file system for both 32-bit and 64-bit operating systems.
> Are there intrinsic limits on ext2, ext3 or ext4?

The structure on disk is one limitation on how large a file can be stored.

Ext2/3: 2TB max file size limit (for typical 4KB block size, less for smaller block sizes)
Ext4: 16TB max file size limit (for typical 4KB block size, less for smaller block sizes)

The other aspect to max file sizes is the kernel and system library. The functions for accessing files need to take values larger than "int". This has not been a problem with distros for years, since like Red Hat 7.1 or something like that.

Another aspect is network transport. For example if a file system that supports 2TB files is shared using an old version of NFS, the network file system itself has limits, and so the maximum file size will be the lesser of the two.

Programs may also be a problem if they don't play well. If a program stores a file pointer in an "int" then it will be unable to deal with large files. Any program compiled using modern includes would show an warning if this mistake was found.

-- 
John Van Ostrand 
CTO, co-CEO 
Net Direct Inc. 
564 Weber St. N. Unit 12, Waterloo, ON N2L 5C6 
Ph: 866-883-1172 x5102 
Fx: 519-883-8533 

Linux Solutions / IBM Hardware 




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