From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jes Sorensen Subject: Re: md raid5 on top of dmcrypt, or dmcrypt on top of md raid5? Date: Fri, 12 Feb 2016 09:34:59 -0500 Message-ID: References: <20160211162959.GG13969@merlins.org> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: (Mikael Abrahamsson's message of "Fri, 12 Feb 2016 10:30:22 +0100 (CET)") Sender: linux-raid-owner@vger.kernel.org To: Mikael Abrahamsson Cc: Marc MERLIN , linux-raid@vger.kernel.org List-Id: linux-raid.ids Mikael Abrahamsson writes: > On Thu, 11 Feb 2016, Marc MERLIN wrote: > >> But can someone confirm that indeed if I have a single md device, >> and 4 CPUs, my throughput is not limited by a single CPU decrypting >> the device? > > There have been multiple discussions about this over time, and since > you didn't qualify "not good" with a number, it's hard to say if this > is your problem or not. About a year ago when I last received a new laptop, I put btrfs on top of luks - it was a rather miserable experience. The system would freeze up and be really slow. I believe the issue was btrfs not acting well with crypto underneath it, and there was hallway talk confirming this but I have no hard data. In the end I gave up and put my /home on xfs on top of LUKS and used btrfs for the uncrypted portions. It may be the btrfs with crypto issues have been resolved since then. Cheers, Jes