Re: Default ext inode size

[Theodore Tso <tytso@mit.edu>]

On Thu, Nov 13, 2008 at 02:56:38PM -0500, Phillip Susi wrote:
> I noticed that the default inode size for mkfs in e2fsprogs has been  
> changed to 256 bytes.  I noticed this because I am seeing users complain  
> that they can no longer access their ext partitions using the windows  
> driver, which only supports normal 128 byte inodes.  I'd like to know  
> why this default was changed.
>
> As I understand it, the larger inode size means that ea/acl can be  
> stored directly in the inode.  Are there any other benefits?  

That's the main one.  The other benefit is that ext4 uses a bigger
inode to store some extra fields such as the file creation time,
nanosecond timestamps, and the 64-bit version number neede which is
used for NFSv4's client-side caching.

> It seems  
> that using extended attributes is rather uncommon in the first place,  

The big user of extended attribute is SELinux, Samba, and Beagle.
Since a number of distributions are now starting to enable SELinux by
default (for better or for worse), it makes a big difference from a
performance perspective for those distributions.

I can't imagine that it would be that hard to fix the Windows driver
to be able to support 258 byte inodes.  It should be a one- or
two-line fix, for those people who care.

					- Ted