Re: dm-crypt and huge performance penalty

[Ryan Castellucci]

On Mon, Sep 20, 2010 at 3:37 PM, Dmitry Nezhevenko <dion@xxxxxxxxx> wrote:
> Firstly I've tried to setup raid5 and then dm-crypt on top of it. After
> discovering issue I've tried just raid5 and confirmed that mdadm itself
> works as expected.
>
> And the last idea is to setup three dm-crypt partitions and then raid5 on
> top of independently encrypted drives.
>
> So here are my results:
>
>           |  mdadm   | mdadm+dm-crypt | 3 x dm-crypt + mdadm |
> Seq. read  | 168 Mb/s | 57 Mb/s        | 119 Mb/s             |
> Seq. write | 80 Mb/s  | 36 Mb/s        | 64.4 Mb/s            |

dm-crypt will only use one core per device, so this is expected
behavior (and I believe an issue that is being worked on). From these
numbers it looks like you have a dual core or dual cpu system?

-- 
Ryan Castellucci http://ryanc.org/
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