howto preallocate to minimize fragmentation

[Ying-Hung Chen <ying@xxxxxxxxxxxxxx>]

Hi there,

we are storing realtime streaming data (multiple/random writes) in our
Linux system with XFS filesystem and suffering from heavy fragementation
(> 90%) . I am wondering what's the best way to reallocate files (say
2GB files) before using the file system.

we are creating the 'quick' sparse file like the following: (is this
cause the problem?)

/bin/dd if=/dev/zero of=/mnt/file.ivf bs=1M seek=2000000 count=1

We are using Linux 2.6.x kernel with XFS filesystem

can anyone help?

Thanks,

-Ying