From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jure =?UTF-8?Q?Pe=C4=8Dar?= Subject: raid5 write performance Date: Fri, 18 Nov 2005 15:05:43 +0100 Message-ID: <20051118150543.59fbdfd9.pegasus@nerv.eu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hi all, Currently zfs is a major news in the storage area. It is very interesti= ng to read various details about it on varios blogs of Sun employees. A= mong the more interesting I found was this: http://blogs.sun.com/roller/page/bonwick?entry=3Draid_z The point the guy makes is that it is impossible to atomically both wri= te data and update parity, which leaves a window of crash that would si= lently leave on-disk data+paritiy in an inconsistent state. Then he men= tions that there are software only workarounds for that but that they a= re very very slow. It's interesting that my expirience with veritas raid5 for example is j= ust that: slow to the point of being unuseable. Now, I'm wondering what= kind of magic does linux md raid5 does, since its write performance is= quite good? Or, does it actually do something regarding this? :) Niel? --=20 Jure Pe=C4=8Dar http://jure.pecar.org - 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