From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: [ANNOUNCE] mdadm-3.1 has been withdrawn Date: Fri, 13 Nov 2009 08:04:20 -0500 Message-ID: <4AFD5954.1010706@tmr.com> References: <19187.50708.551325.297625@notabene.brown> <4AF829B2.5090001@redhat.com> <4AF836F8.5040903@panix.com> <4AF8847D.8030303@redhat.com> <4AFC8B6D.7080603@tmr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Mikael Abrahamsson Cc: Doug Ledford , Jon Nelson , linux-raid@vger.kernel.org List-Id: linux-raid.ids Mikael Abrahamsson wrote: > On Thu, 12 Nov 2009, Bill Davidsen wrote: > >> I like 1.2, I feel it's least likely to suffer collateral damage, and >> the problems it causes seem to result in the type of behavior you >> mention aboue, the system says "Can't, won't, you don't know what >> you're doing." > > What about adding a new v1.3 superblock which basically has 4 > superblocks, an old 1.x superblock residing at - size> (new location), and then pointers to this block residing where > 1.0, 1.1 and 1.2 superblocks would normally be? Wouldn't that solve > "everybodys" problem by making it easier to find the superblock > regardless of what might have happened (drive size changed because of > 3ware, someone installed mbr on the drive etc). > Is it because it's early in the morning and I haven't had coffee, or is that starting to sound like raid-1 with superblocks? I just have to feel that it would increase the chances of something "looking like" a superblock, but wasn't. Then we could have reshape of superblocks in --grow, all in all that idea feels as though it's inviting them to be different. Imagine an array with partitions, each of which is in an array (like raid-1+0) with superblocks everywhere. I'm sure other people will have thoughts on this, but given the problems we have with mismatch_cnt in mirrors, I wouldn't trust them to stay the same. And all would have to be updated, of course, makes for much disk writing. -- Bill Davidsen "We can't solve today's problems by using the same thinking we used in creating them." - Einstein