From mboxrd@z Thu Jan 1 00:00:00 1970 From: "=?ISO-8859-15?Q?Stefan_/*St0fF*/_H=FCbner?=" Subject: Re: MD RAID Bug 7/15/12 Date: Sun, 30 Sep 2012 23:08:15 +0200 Message-ID: <5068B4BF.6000807@gmail.com> References: <022FFCA9-5D0E-41DB-9617-202C6FAADD06@rightthisminute.com> Reply-To: st0ff@npl.de Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Chris Murphy Cc: Linux RAID List-Id: linux-raid.ids Am 30.09.2012 04:47, schrieb Chris Murphy: > > On Sep 29, 2012, at 6:12 PM, Mark Munoz wrote: > >> >> Configuration: >> md0 is a RAID 6 volume with 24 devices and 1 spare. It is working fine and was unaffected. >> md1 is a RAID 6 volume with 19 devices and 1 spare. It was affected. All the drives show as unknown raid level and 0 devices. With the exception of device 5. It has all the information. >> >> Layout : left-symmetric >> Chunk Size : 4K > > Off topic response: I'm kindof new at all of this. But 24 and 19 devices? Is this really ideal? Why not cap RAID6 to a max of 12 disks, and either use LVM or md raid linear to aggregate? > Also off topic: 12 drives would be as "nearly unalignable" as 19 are. But still this setup is kind of sporty. I wouldn't put too expensive data on there. My rule of thumb: each 4 drives need one drive of redundancy. So a ten drive raid6 is good. Next alignment step (powers of two amount of data drives) would be 18 - I'd add spare to it. But 45 drives? I'd give it a RAID60 of 4x10 drives, then think about it again, what to do with those other 5 drives... or 2x18+1x6 and 3 spares ... Well, whatever. This is not an ideal setup anyhow. God bless Supermicro SC847E16JBOD ;) St0fF