From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Dilger Date: Wed, 17 Oct 2001 16:30:56 -0600 Message-ID: <20011017163056.A508@turbolinux.com> References: <20011018000006.A22777@jensbenecke.de> Mime-Version: 1.0 Content-Disposition: inline In-Reply-To: <20011018000006.A22777@jensbenecke.de> Subject: [linux-lvm] Re: [reiserfs-list] Horrid performance with 2.4.{9,10,12} + LVM + ReiserFS Sender: linux-lvm-admin@sistina.com Errors-To: linux-lvm-admin@sistina.com Reply-To: linux-lvm@sistina.com List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Id: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ReiserFS Mailingliste , LVM List On Oct 18, 2001 00:00 +0200, Jens Benecke wrote: > The LVM volume is about 97% full (7.5GB free). In ext2 the rule was not to > use the last 5% of a disk because it would be too slow. But I think this > should not be a problem for ReiserFS, at least not with such big disks (?). > If it is, this would waste over 10GB disk space which I don't think is > acceptable. Do you mean that you have 3% of the LOGICAL VOLUME or DISK free, or do you have 3% of the FILESYSTEM free (e.g. is the free space reported by "pvscan" or "df")? If it is the FILESYSTEM with only 3% free, then there is not much that you can do about the performance problem - fragmentation cannot be helped, regardless of the filesystem. Actually, there is someone testing exactly this issue with reiserfs, and they report 5-10x slowdown with a highly fragmented filesystem, so your 2.5x slowdown is in the right range. > Strangely, on a 'real' partition this is much faster (this was formatted > recently and with 3.6 format, though): Yes, well a new filesystem (especially if not full) will not have fragmentation problems. > Currently I'm thinking of backing up the whole volume and reformatting, but > I wanted to ask what might cause this first because this would be a major > PITA for many users here. Well, it may help for a short time, but at 97% full you will have problems almost right away again. I'd suggest adding more space to the LV and growing the filesystem (without doing the backup/restore) and you will naturally get some "defragmentation" happening as the new space is used and old space is freed. Cheers, Andreas -- Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto, \ would they cancel out, leaving him still hungry?" http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert