From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Docs and operation of RAID10, size limitations on 0.90 Date: Wed, 30 Jul 2008 12:18:06 -0400 Message-ID: <4890943E.5060608@tmr.com> References: <20080728143553.GE30681@nexus.edgeofthenet.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080728143553.GE30681@nexus.edgeofthenet.org> Sender: linux-raid-owner@vger.kernel.org To: Richard Michael Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Richard Michael wrote: > Hello list, > > I'm building a new system with 8 disks, in two RAID5 arrays of 4 disks > each, and a RAID1 array across them. (Then LVM2 on top of the RAID1 > array.) > > I approached it this way for two reasons: > > 1/ It feels "cleanest"; in the sense that it's not a special case, it's > just RAID1 with two devices, which happen to be RAID5. > > 2/ I have a particular usage in mind: I need to be able to split the > mirror and remove half; return it later and resync. Therefore, I want > to know which disks comprise which halves. > > However, I'm rethinking toward RAID10. However, I can't find much > documentation about layout, etc. I believe this was recently discussed > on the list. > > > Can someone with RAID10 experience enlighten me? Can it be cleaned > split, half moved to another host, or rejoined with the first half, etc. > How about performance? (Not a huge issue, but it is better than nested > arrays as I first considered?) > 10,f2 read performance is very good, write performance is okay. AFAIK you can't do a split, the object is to spread head motion and improve performance. > > Aside, I'd like it to be bootable. I was told grub only supports > booting from 0.90 superblocks, but that 0.90 has a 2TB limitation? > Meaning, I need /boot with 0.90 and another partition (LVM) with a 1.0 > superblocks? > I usually create a 100MB or so partition, raid1, on my drives and boot off that using 0.90 superblock. The rest of the storage can be anything you want. -- Bill Davidsen "Woe unto the statesman who makes war without a reason that will still be valid when the war is over..." Otto von Bismark