Re: call for brave ext4 testers in F9, with caveats

[Eric Sandeen <sandeen redhat com>]

Matej Cepl wrote:
> On 2008-02-04, 17:23 GMT, Eric Sandeen wrote:
>> Rawhide and the F9 alpha can install onto an ext4dev filesystem 
>> root; first you need to tell (a.k.a. lie to) the installer with
>> "iamanext4developer" on the boot commandline.  This is akin to the "jfs"
>> or "reiserfs" options for those filesystems, but a higher hurdle (more
>> characters to type!).
> 
> Do I have to reinstall, or I can switch some partitions (probably 
> starting with /var -- it will take some time, before I will use 
> it for /home ;-)) 

Take your time... :)  As I said; smoke-tests first, please!

> to ext4 on the already working Rawhide?

You can explicitly mount it as -t ext4dev, and the next file created
will make a non-backwards-compatible change when it writes in extent
format.  From then on, it's an "ext4dev" filesystem with mostly
non-extent ext3 files on it.  :)

There is a full migration tool in the works, but it's not ready for
primetime yet.

Also, some ext4 features won't be available on a filesystem with the
(was-default) 128-byte inode size.  (nanosecond timestamps come to mind)

-ERic