From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: What do Events actually mean? Date: Tue, 25 Mar 2008 14:58:06 +1100 Message-ID: <18408.30798.940744.724391@notabene.brown> References: <47DD2CD7.2090802@tuxes.nl> <20080316161451.0d17fd22@szpak> <47E26775.3000500@tuxes.nl> <20080320134747.GA28114@cthulhu.home.robinhill.me.uk> <47E2725C.1020206@tuxes.nl> <20080320163551.GG13719@mit.edu> <47E2EE64.5080101@rabbit.us> <47E3C504.3010700@tmr.com> <47E3CBAF.4090808@rabbit.us> <47E43E57.5010409@tmr.com> <20080321235557.GA11801@cthulhu.home.robinhill.me.uk> <47E4D95A.9000505@rabbit.us> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: message from Justin Piszcz on Saturday March 22 Sender: linux-raid-owner@vger.kernel.org To: Justin Piszcz Cc: linux-raid@vger.kernel.org, Peter Rabbitson List-Id: linux-raid.ids On Saturday March 22, jpiszcz@lucidpixels.com wrote: > > > On Sat, 22 Mar 2008, Peter Rabbitson wrote: > > > Robin Hill wrote: > >> On Fri Mar 21, 2008 at 07:01:43PM -0400, Bill Davidsen wrote: > >> > >>> Peter Rabbitson wrote: > > > UUID : b6a11a74:8b069a29:6e26228f:2ab99bd0 (local to host Arzamas) > > Events : 0.183270 > > > > As you can see it is pretty old, and does not have many events to speak of. > > What do the 'Events' actually represent and what do they mean for RAID0, > RAID1, RAID5 etc? An 'event' is one of: switch from 'active' to 'clean' switch from 'clean' to 'active' device fails device is added spare replaces a failed device after a rebuild I think that it all. None of these are meaningful for RAID0, so the 'events' counter on RAID0 should be stable. Unfortunately, the number looks like a decimal but isn't. It is a 64bit number. We print out the top 32 bits, then the bottom 32 bits. I don't remember why. Maybe I'll 'fix' it. > > How are they calculated? events = events + 1; Feel free to merge this text into the wiki. NeilBrown