[KLUG Members] ext3 size limits

[Adam Williams]

>Would I have a problem using a 1TB external SCSI RAID array under Linux 
>with an EXT3 filesystem?

With 2.4.x you have a maximum *FILE* size of ~16 terabytes.  

Maximum *FILESYSTEM* size with ext2/3 without tweaking anything is ~4
terabytes.  This assumes a 4k block size, and on Intel 32-bit I think
you are limited to page size no larger than PAGE_CACHE_SIZE, which is 4k
on most processors.  Still, your 1TB is well within the 4TB limit.

*BUT* what are you going to be storing in this filesystem?  If it is
lots of small files the above arrangement will be terribly inefficient
and you will be "full" long before the file system is "full".  Or
incredibly large files?  ext2/3 goes over to double indirect allocation
on REALLY big files, and that is REALLY slow.  

Also, if you use ext2/3 on a file system this size be sure to allocate
more than the default number of inodes.  Every directory, file, pipe,
socket, etc... takes an inode.  And your stuck with the number you
created when you made the file system.  If you aim high you shouldn't
have a problem.

It is hard to give good advice without knowing what you will be using
the file system for,  but at this size there are quite a few
considerations to take into account.

Not meant to scare you off doing it, I know people who run ext2/3 file
systems of this size without problems.  But it helps to setup the file
system correctly.  

Do you have a separate physical volume (or partition on the RAID device)
for the journal?
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