Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932441AbWHCJfU (ORCPT ); Thu, 3 Aug 2006 05:35:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932442AbWHCJfT (ORCPT ); Thu, 3 Aug 2006 05:35:19 -0400 Received: from embla.aitel.hist.no ([158.38.50.22]:18331 "HELO embla.aitel.hist.no") by vger.kernel.org with SMTP id S932441AbWHCJfT (ORCPT ); Thu, 3 Aug 2006 05:35:19 -0400 Date: Thu, 3 Aug 2006 11:32:13 +0200 To: Wil Reichert Cc: Krzysztof Halasa , Kyle Moffett , Ian Stirling , David Masover , David Lang , Nate Diller , Adrian Ulrich , "Horst H. von Brand" , ipso@snappymail.ca, lkml@lpbproductions.com, Jeff Garzik , "Theodore Ts'o" , LKML Kernel , reiserfs-list@namesys.com Subject: Re: Solaris ZFS on Linux Message-ID: <20060803093213.GA12071@aitel.hist.no> References: <5c49b0ed0607311705t1eb8fc6bs9a68a43059bfa91a@mail.gmail.com> <20060801010215.GA24946@merlin.emma.line.org> <44CEAEF4.9070100@slaphack.com> <44CED95C.10709@slaphack.com> <44CFE8D9.9090606@mauve.plus.com> <0DA0B214-50BC-4E20-A520-B7AB121BB38B@mac.com> <7a329d910608021920h6c1bb625q5336115cfd253adf@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7a329d910608021920h6c1bb625q5336115cfd253adf@mail.gmail.com> User-Agent: Mutt/1.5.12-2006-07-14 From: Helge Hafting Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1966 Lines: 42 On Wed, Aug 02, 2006 at 07:20:25PM -0700, Wil Reichert wrote: > On 8/2/06, Krzysztof Halasa wrote: > >Kyle Moffett writes: > > > >> IMHO the best alternative for a situation like that is a storage > >> controller with a battery-backed cache and a hunk of flash NVRAM for > >> when the power shuts off (just in case you run out of battery), as > >> well as a separate 1GB battery-backed PCI ramdisk for an external > >> journal device (likewise equipped with flash NVRAM). It doesn't take > >> much power at all to write a gig of stuff to a small flash chip > >> (Think about your digital camera which runs off a couple AA's), so > >> with a fair-sized on-board battery pack you could easily transfer its > >> data to NVRAM and still have power left to back up data in RAM for 12 > >> hours or so. That way bootup is fast (no reading 1GB of data from > >> NVRAM) but there's no risk of data loss. > > > >Not sure - reading flash is fast, but writing is quite slow. > >A digital camera can consume a set of 2 or 4 2500 mAh AA cells > >for a fraction of 1 GB (of course, only a part of power goes > >to flash). > > Seeks are fast, throughput is terrible, power is minimal: > > http://techreport.com/reviews/2006q3/supertalent-flashide/index.x?pg=1 > That particular flash drive had terrible througput. But there are other alternatives. I use a kingston 4GB compactflash card as a disk, and it reads 22MB/s, according to specs and tests with hdparm. And it writes 16MB/s. Much better than the sorry thing in that test, about the same read speed as their worst platter-based harddisk. And of course it still have the nice seek times of non-rotating media. :-) Helge Hafting - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/