From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Turmel Subject: Re: RAID 10 / 2 Devices Layout question Date: Tue, 28 Jun 2016 14:16:13 -0400 Message-ID: <5772BEED.9010404@turmel.org> References: <5770120D.9050809@turmel.org> <20160628142502.7e69983d@natsu> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160628142502.7e69983d@natsu> Sender: linux-raid-owner@vger.kernel.org To: Roman Mamedov Cc: Paul Roland , linux-raid@vger.kernel.org List-Id: linux-raid.ids On 06/28/2016 05:25 AM, Roman Mamedov wrote: > On Sun, 26 Jun 2016 13:34:05 -0400 > Phil Turmel wrote: > >> On 06/26/2016 01:20 PM, Paul Roland wrote: >> >>> I have two SSDs, and I would like to use md/raid10 (2devices) for >>> performance reasons. >> >> Ok, that's reasonable. > > Maybe I'm missing something, but how is a RAID10 of just two devices is > considered reasonable without any questions or explanation? What is the actual > layout that is expected here, and what benefits (or even differences) does it > have compared to RAID0? I thought you need at least 3 devices (and h/w RAID > controllers might even require 4) for RAID10 to start making sense. Paul made a statement that isn't obviously a problem -- raid10 on SSDs makes a blistering fast general purpose redundant setup. I use precisely this setup for my boot and OS devices. I'd do it for my databases too if I could afford it. (Can't justify it for my performance needs -- darn.) If Paul had asked whether or not to use raid10, I'd have had follow up questions on his application.