[COLUG] dd alternatives

[Greg Sidelinger]

I'm finally getting around to setting up dm-crypt on CentOS 5 and they  
suggested writing 0's to the encrypted block device before formatting  
it. This was not an issue when I did swap since that's only 2G but  
when doing an 900G sata hardware raid 5 array its taking forever with  
dd.

dd if=/dev/zero of=/dev/mapper/encrypted-fs

I tried different bs=... settings but nothing would go faster than  
5M/s after a few min. I'm checking speeds by sending a signal USR1 to  
the dd process. I know raid 5 is slow at writes but i'm looking at a  
few days for the operation to complete. hdparm also did not show any  
options for this controller to tweak other than read ahead.

I know I saw something once that was faster than dd but I can't recall  
what it was and google was not helping. Can anyone give suggestions on  
a faster way to do this. Course I may just be hitting the limits of  
the hardware with encryption and I need to just let it go.

Greg