From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc MERLIN Subject: Re: Very long raid5 init/rebuild times Date: Tue, 21 Jan 2014 08:37:55 -0800 Message-ID: <20140121163755.GG10140@merlins.org> References: <20140121073540.GF10140@merlins.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20140121073540.GF10140@merlins.org> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Mon, Jan 20, 2014 at 11:35:40PM -0800, Marc MERLIN wrote: > Howdy, > > I'm setting up a new array with 5 4TB drives for which I'll use dmcrypt. > > Question #1: > Is it better to dmcrypt the 5 drives and then make a raid5 on top, or the opposite > (raid5 first, and then dmcrypt) > I used: > cryptsetup luksFormat --align-payload=8192 -s 256 -c aes-xts-plain64 /dev/sd[mnopq]1 I should have said that this is seemingly a stupid question since obviously if you encrypt each drive separately, you're going through the encryption layer 5 times during rebuilds instead of just once. However in my case, I'm not CPU-bound, so that didn't seem to be an issue and I was more curious to know if the dmcrypt and dmraid5 layers stacked the same regardless of which one was on top and which one at the bottom. Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/