From mboxrd@z Thu Jan 1 00:00:00 1970 From: Erik Mouw Subject: Re: NVRAM support Date: Fri, 10 Feb 2006 13:42:05 +0100 Message-ID: <20060210124204.GC28676@harddisk-recovery.com> References: <43EC5655.1060504@web.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <43EC5655.1060504@web.de> Sender: linux-raid-owner@vger.kernel.org To: Mirko Benz Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Fri, Feb 10, 2006 at 10:01:09AM +0100, Mirko Benz wrote: > Does a high speed NVRAM device makes sense for Linux SW RAID? E.g. a PCI > card that exports battery backed memory. Unless it's very large (i.e.: as large as one of your disks), it doesn't make sense. It will probably break less often, but it doesn't help you in case a disk really breaks. It also won't speed up an MD device much. > Could that significantly improve write speed for RAID 5/6 (e.g. via an > external journal, asynchronous operation and write caching)? You could use it for an external journal, or you could use it as a swap device. > What changes would be required? None, ext3 supports external journals. Look for the -O option in the mke2fs manual page. Using the NVRAM device as swap is not different from a using "normal" swap partition. Erik -- +-- Erik Mouw -- www.harddisk-recovery.com -- +31 70 370 12 90 -- | Lab address: Delftechpark 26, 2628 XH, Delft, The Netherlands