From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Greaves Subject: Re: Spare disk could not sleep / standby Date: Tue, 08 Mar 2005 08:51:58 +0000 Message-ID: <422D67AE.1000506@dgreaves.com> References: <422D327D.11718.F8DB3@localhost> <200503080414.j284EG510309@www.watkins-home.com> <16941.11443.107607.735855@cse.unsw.edu.au> <62b0912f0503072120776e0b56@mail.gmail.com> <16941.14813.465306.72004@cse.unsw.edu.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit In-Reply-To: <16941.14813.465306.72004@cse.unsw.edu.au> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Neil Brown wrote: >As the event count needs to be updated every time the superblock is >modified, the event count will be updated forever active->clean or >clean->active transition. All the drives in an array must have the >same value for the event count, so the spares need to be updated even >though they, themselves, aren't exactly 'active' or 'clean'. > > May I ask why? I can understand why the active drives need to have the same superblock - it marks the data set as consistent and is used on restart to indicate integrity across the set and avoid a resync. But the spare has no data on it. What does it mean that the superblock is up to date? In fact isn't that misleading? Surely, if anything, the spare _should_ have an out of date superblock? David