ext4 testing in the F10 release cycle

[Richard W.M. Jones]

On Wed, Sep 03, 2008 at 11:19:04AM -0500, Eric Sandeen wrote:
> I'd appreciate any and all testing, benchmarking & feedback that people
> would be willing to do.  Just getting more exposure in real-life
> scenarios would be great.
> 
> As with any filesystem, I wouldn't put your only copy of your most
> precious data on it - use good sense about backups etc - but ext4 has
> made good progress since F9 on both stability and performance, so have
> at it!

Persistent pre-allocation[1] is something that virt-manager could
really use when it has to allocate multi-gigabyte images.  A few
questions about this feature though:

(a) Is it exposed as a syscall anywhere?  I don't see it in the header
files of my Rawhide system (2.6.27).

(b) Will preallocate "do the right thing" on filesystems that don't
directly support it?

(c) Does ext4 preallocate in the background?  A synchronous
preallocate call isn't much use to virt-manager.

Rich.

[1] http://en.wikipedia.org/wiki/Ext4#Persistent_pre-allocation

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
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