Hi,
That's what I was thinking too but the machine is a dual core 2.4 and the 2 cores are alternating between 43% and 57% (one on each then swapping). I assume that random generation is a compute-bound activity so if that was the bottleneck I would have expected near on 100% both sides.
When I used dd to copy the Windows partition from the SATA drive to the new one via a USB dongle I was getting 29MBps with bs=8M.
Don't know why this thing is so slow.
Cheers,
Paul.
Sent from my BlackBerry® wireless device
-----Original Message-----
From: "Antony" <ar@???>
Date: Mon, 22 Dec 2008 19:41:21
To: <hampshire@???>
Subject: Re: [Hampshire] Ubuntu LVM LUKS
"Vic" wrote:
> > I got a howto online with the steps to configure the last version of
> > Ubuntu for LUKS LVM. One of the things it tells you to do is a "dd
> > /dev/urandom /dev/sda5" to fill the LVM group with random noise before
> > creating the groups. I have started this but I'm only getting 1.7MBps so
> > it's going to take nearly 3 days to complete on a 300GB partition!
>
> I wouldn't bother with that step. Not having random stuff across your
> partition will probably make it a little easier for an experienced
> investigator to find the bits that make up your filesystem - but you're
> not relying on that for security, are you?
Presumably what you don't want the investigator to find is not so much
the filesystem as what was on the disk beforehand.
What's the bottleneck according to the system monitor and top? It's a
bit hard to believe the 1.7MBps results from pseudo random generation,
much less the encryption or disk system, but maybe filling from
/dev/zero would help as a compromise?
Anthony
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