From mboxrd@z Thu Jan 1 00:00:00 1970 From: Goswin von Brederlow Subject: Re: mismatch_cnt again Date: Tue, 17 Nov 2009 05:50:27 +0100 Message-ID: <87lji5lppo.fsf@frosties.localdomain> References: <200911162136.nAGLatPb028438@wind.enjellic.com> <20091117091455.33c8757c@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <20091117091455.33c8757c@notabene.brown> (Neil Brown's message of "Tue, 17 Nov 2009 09:14:55 +1100") Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: greg@enjellic.com, Eyal Lebedinsky , linux-raid list List-Id: linux-raid.ids Neil Brown writes: > On Mon, 16 Nov 2009 15:36:55 -0600 > greg@enjellic.com wrote: > >> If a scrub directive were to be implemented it would be beneficial to >> make it interruptible. A 'halt' or similar directive would shutdown >> the scrub and latch the last block number which had been examined. >> That would allow a scrub to be resumed from that point in a subsequent >> session. >> >> With some of these large block devices it is difficult to get through >> an entire 'check/scrub' in whatever late night window is left after >> backups have run. The above infra-structure would allow userspace to >> gate the checking into whatever windows are available for these types >> of activities. > > This is already possible with check. > > If you write 'idle' to 'sync_action', the check will stop. > If you first read from 'sync_completed' and store that value, > then before starting a new 'check', write the value to > sync_max, then you get exactly what you are asking for, all > easily done in a shell script. > You can also set 'sync_max' if you like, thus you could e.g. > quite easily have a cron job that scrubs 1/28th of the array each > night based on the day of the month. > > NeilBrown Great. I was looking for that feature too. MfG Goswin