[clug] how long to encrypt a 1T exernal disk using LUKS

Daniel Pittman daniel at rimspace.net
Sun Jun 27 18:49:43 MDT 2010

jhock <jhock at iinet.net.au> writes:

> I have an eeepc 10HD with Ubuntu 10.0 and Western Digital 1 terabyte
> external hard disk. I started encrypting the WD disk yesterday using
> gdecrypt and luks. Does anyone know how long this could take. It is still
> encrypting this morning. So far top tells me the kcrypt command has been
> running for "1075:00". I expect that it minutes.

Yeah, that counts minutes of *CPU* time spent running — which is different
from wall-clock minutes, but probably not by too much.

I was going to say "wow, that is a lot longer than I would expect", but then
I noticed the "eeepc" bit, which means an Atom core, right?

Between a USB connection for the disk (I assume) and a CPU that is slower
than a wet weekend, it wouldn't shock me that it took that long.  When I
benchmarked the basic encryption stuff on an Atom vs a Core2 CPU it came out
six or eight times slower.

Those chips are hella-slow, and it is going to have to do a *lot* of
encryption to fill out the entire 1TB of data.

You can get some idea of performance by running 'openssl speed' for the
algorithms you actually use on an otherwise unloaded Atom core, but keep in
mind that I/O delays and the kcryptd architecture might deliver less than
the theoretical maximum performance in the real world.

✣ Daniel Pittman            ✉ daniel at rimspace.net            ☎ +61 401 155 707
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