[mdlug] Best File System for 1TB Raid5

[Dan Pritts]

as others have mentioned ext3 is plenty stable.  Your errors were
(almost certainly) not due to ext3 bugs but hardware errors.

ext3 is arguably not the "best"; it has some old design constraints
which can be a bummer.  I think, for instance, that directories are
stored as linked lists, which makes parsing a large directory very,
very slow.   It has some other speed issues in some cases.

I think ext3 is limited to 4TB filesystems but I might be wrong.
Not an issue in this particular case.

It defintely pre-allocates inodes, which is kind of a bummer.
You have to devote a non-trivial amount of space to inodes, and it's
useless for anything else; and if you run out, you're hosed. 
XFS and JFS both dynamically allocate inodes.


the wikipedia articles have a good summary of each filesystem:
http://en.wikipedia.org/wiki/Ext3
http://en.wikipedia.org/wiki/XFS
http://en.wikipedia.org/wiki/JFS

Personally, i use XFS.  JFS and ext3 are both also reasonable choices
and for the majority of the cases any of them will be fine.

ps - if you *do* use XFS, make sure to get a recent kernel; the XFS
folks have been actively working the last couple years.  If you use
centos/RHEL, there is an XFS kernel module RPM in centosplus that
has recent XFS code.


On Tue, Jul 08, 2008 at 10:54:19PM -0400, Stan Green wrote:
> I recently added three 500gb SATA drives, using a Promise SATA300 Tx4 
> controller, configured with software Raid as Raid5. The file system is EXT3. 
> However, I have seen two instances of EXT3 becoming read-only due to errors. 
> I have had to run fsck.ext3 have seen a large (+200) number of errors in the 
> file system. (Not sure why.)
> 
> This got me to thinking is EXT3 the best, most stable, file system for this 
> size of partition? The data includes both very large files (+4GB) and a large 
> number of small files. From what I have read so far, it look like either JFS 
> or XFS might be the way to go. 
> 
> I am still in testing mode for this configuration, so I can change file 
> systems if it will result in a better system. 
> 
> Any thoughts on what file system would be best for this configuration?
> 
> Thanks,
> Stan Green
> 
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danno
--
dan pritts
danno at umich.edu
734-929-9770