From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tobias Hofmann Subject: Re: Spare disk could not sleep / standby Date: Wed, 09 Mar 2005 10:03:47 +0100 Message-ID: <422EBBF3.70201@medien.uni-weimar.de> 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> <62b0912f05030721465e84e4da@mail.gmail.com> <16941.16439.595486.231598@cse.unsw.edu.au> <62b0912f050307222494fe17f@mail.gmail.com> <422D625C.5020803@medien.uni-weimar.de> <62b0912f0503080057488f13ad@mail.gmail.com> <422D83B1.5060709@medien.uni-weimar.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 08.03.2005 14:13, Gordon Henderson wrote: > On Tue, 8 Mar 2005, Tobias Hofmann wrote: [...] >>I had found postings on the net claiming that doing so without >>unmounting the fs on the raid, this would lead to bad things happening - >> but your report seems to prove them wrong... > > > I've been using something called noflushd on a couple of small "home > servers" for a couple of years now to spin the disks down. I made a > posting about it here some time back and the consensus seemed to be (at > the time) that it all should "just work"... And indeed it has been just > working. Thanks for mentioning this... > They are only running RAID-1 though, 2.4 and ext2. I understand the ext3 > would force spin-up every 5 seconds which would sort of defeat it. There > are other things to be aware of to (things that will defeat using hdparm) > - making sure every entry in syslog.conf is -/var/log/whatever (ie. with > the hyphen prepended) to stop if doing the fsync on every write which will > spin up the disks. They are on UPSs, but they have been known to run-out > in the past )-: so a long fsck and some data loss is to be expected. > > Essentially noflushd blocks the kernel from writing to disk until memory > fills up.. So most of the time the box sits with the disks spun down, and > only spins up when we do some file reading/saving to them. ...and this is no prob for me, as my idea is to only spin down a raid used for data, not OS... > Noflushd is at http://noflushd.sourceforge.net/ and claims to work with > 2.6, but says it will never work with journaling FSs like ext3 and XFS. > (which is understandable) ...true, but bites me. I,ll still look into it, once I am free to fool around with the raid (which currently is a backup, so I,d hesitate to "kill" it... :) greets, tobi... :)