From mboxrd@z Thu Jan 1 00:00:00 1970 From: it Subject: Re: block level vs. file level Date: Sun, 12 Feb 2006 17:16:39 -0800 Message-ID: <43EFDDF7.6090405@kfa.org> References: <43EF8CFB.5080403@kfa.org> <20060212213157.GX32687@strugglers.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20060212213157.GX32687@strugglers.net> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids > > >Yes, and it's a pain, but if you have to deal with it I think the >wealth of options in md leaves you better able to handle it than >with hardware RAID. Here's something that happened to me: > >http://strugglers.net/wiki/becks.strugglers.net > Ouch. How does hardware raid deal with this? Does it? Thanks, A. Andy Smith wrote: >On Sun, Feb 12, 2006 at 11:31:07AM -0800, it wrote: > > >>The hardware raid does the mirroring on the block level, so it's >>actually /dev/sda mirroring /dev/sdb - the whole drive, and not >>partitions. There is a way to set this up on software raid. It takes >>more configuration tweaking, but the mirroring then includes the >>partition table as well. This way, if a drive fails, one can replace it >>without pre-partitioning it. >> >> > >That can be less flexible though. If I have say 4 drives then I >quite often want small /boot, / and swap under RAID-1 then the rest >as a single large partition in RAID-5, -6 or -10 as an LVM PV. > > > >>This also raises another point, which is relevant for both cases - same >>exact models of hard disks have different number of cylinders, so if a >>RAID partition is created on a larger drive it cannot be mirrored to a >>smaller drive. >> >> > >Same exact models don't usually have different block counts, but >certainly if you replace a dead drive with a different one of the >same advertised capacity you can end up getting one slightly >smaller. > > > >>Does anyone have any experience with this? >> >> > >Yes, and it's a pain, but if you have to deal with it I think the >wealth of options in md leaves you better able to handle it than >with hardware RAID. Here's something that happened to me: > >http://strugglers.net/wiki/becks.strugglers.net > > >