From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?Q?Mathias_Bur=C3=A9n?= Subject: Re: Performance question, RAID5 Date: Mon, 31 Jan 2011 09:37:46 +0000 Message-ID: References: <20110130094444.68288b0e@natsu> <20110130171533.4c9e236b@natsu> <4D45C3FA.2040900@hardwarefreak.com> <20110131085202.GA25912@www2.open-std.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20110131085202.GA25912@www2.open-std.org> Sender: linux-raid-owner@vger.kernel.org To: =?UTF-8?Q?Keld_J=C3=B8rn_Simonsen?= Cc: Stan Hoeppner , Roman Mamedov , CoolCold , Linux-RAID List-Id: linux-raid.ids On 31 January 2011 08:52, Keld J=C3=B8rn Simonsen wro= te: > If your intallation is CPU bound, and you are > using an Atom N270 processor or the like, well some ideas: > > The Atom CPU may have threading, so you could run 2 RAIDs > which then probably would run in each thread. > It would cost you 1 more disk if you run 2 RAID5's > so you get 8 TB payload out of your 12 GB total (6 drives of 2 TB eac= h). > > Another way to get better performance could be to use less > CPU-intensitive RAID types. RAID5 is intensitive as it needs to > calculate XOR information all the time. Maybe a mirrored > raid type like RAID10,f2 would give you less CPU usage, > and the run 2 RAIDS to have it running in both hyperthreads. > Here you would then only get 6 TB payload of your 12 GB disks, > but then also probably a faster system. > > Best regards > keld > Hi, It's interesting what you say about the XOR calculations. I thought that it was only calculated on writes? The Atom (330) has HT, so Linux sees 4 logical CPUs. // Mathias -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html