From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans Reiser Subject: Re: the " 'official' point of view" expressed by kernelnewbies.org regarding reiser4 inclusion Date: Wed, 09 Aug 2006 03:15:26 -0600 Message-ID: <44D9A7AE.5060405@namesys.com> References: <200608011428.k71ESIuv007094@laptop13.inf.utfsm.cl> <44CF87E6.1050004@slaphack.com> <20060806225912.GC4205@ucw.cz> <44D99ED9.1030003@namesys.com> <20060809094813.GE3308@elf.ucw.cz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com In-Reply-To: <20060809094813.GE3308@elf.ucw.cz> List-Id: Content-Type: text/plain; charset="us-ascii" To: Pavel Machek Cc: David Masover , "Horst H. von Brand" , Bernd Schubert , reiserfs-list@namesys.com, Jan-Benedict Glaw , Clay Barnes , Rudy Zijlstra , Adrian Ulrich , ipso@snappymail.ca, lkml@lpbproductions.com, jeff@garzik.org, tytso@mit.edu, linux-kernel@vger.kernel.org Pavel Machek wrote: >On Wed 2006-08-09 02:37:45, Hans Reiser wrote: > > >>Pavel Machek wrote: >> >> >> >>>Yes, I'm afraid redundancy/checksums kill write speed, >>> >>> >>> >>they kill write speed to cache, but not to disk.... our compression >>plugin is faster than the uncompressed plugin..... >> >> > >Yes, you can get clever. But your compression plugin also means that >single bit error means whole block is lost, so there _is_ speed >vs. stability-against-hw-problems. > >But you are right that compression will catch same class of errors >checksums will, so that it is probably good thing w.r.t. stability. > > Pavel > > So we need to use ecc not checksums if we want to increase reliability. Edward, can you comment in more detail regarding your views and the performance issues for ecc that you see?