From mboxrd@z Thu Jan 1 00:00:00 1970 From: Goswin von Brederlow Subject: Re: linux disk access when idle Date: Sat, 22 Aug 2009 08:37:16 +0200 Message-ID: <87zl9sjqw3.fsf@frosties.localdomain> References: <20090820163522.GA29215@sewage> <4A8F190B.9010406@tmr.com> <20090821231039.GB22331@sewage> <20090822050416.GA9202@musti.tarvainen.info> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: <20090822050416.GA9202@musti.tarvainen.info> (Tapani Tarvainen's message of "Sat, 22 Aug 2009 08:04:17 +0300") Sender: linux-raid-owner@vger.kernel.org To: linux-raid List-Id: linux-raid.ids Tapani Tarvainen writes: > Just a data point: I've got a box (Debian Lenny) with five disks, > system disk plus 4-disk RAID5 array, used as a backup server > (rsnapshot), and I power the disks in the raid array down after > running the backup - and they stay powered down, even though I don't > umount the filesystems let alone stop the array. When accessed (like > for restoring something from the backup), they wake up, so I've got an > hourly cron job powering them down again - but most days (when > there're no restores) they are powered up only during the backup run. > > So it can be done. It's not filesystem type dependent either, there's > one jfs and one ext3 in the array. > > The system disk stays up, though. Some experimenting suggested > that getting it to stay down would require putting /tmp and parts > of /var on a ramdisk (/var/log at least), but I didn't go to > the trouble of tracking down all disk-awakening services. Same here. I have a raid1 for the system on 2 drives and a raid5 over 6 drives for data. The raid5 is ext3 powers down after 15 minutes without access. The raid1 stays up all the time due to /var/log/syslog being written to too often. /tmp is tmpfs though. MfG Goswin