From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcel Lohmann Subject: Re: btrfs on LVM: Out of space Date: Wed, 8 Sep 2010 22:35:03 +0200 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 To: linux-btrfs@vger.kernel.org Return-path: In-Reply-To: List-ID: 2010/9/8 Zhu Yanhai : > Hi, > Have you ever tried with 'mkfs.btrfs -m single /dev/xxxx'? > As you had a RAID1 based on LVM, you don't have to keep > the default duplicated metadata profile in Btrfs. > > -zyh > > 2010/9/8 Marcel Lohmann : >> In that complete logical volume I created a btrfs partition. And >> btrfs-show displays 130GB space. Fine. >> to give me the actual numbers. And that tells me: >> Data: total=23.97GB, used=23.97GB >> Metadata: total=53.01GB, used=33.98GB >> System: total=12.00MB, used=16.00KB No, I did not try this. I just created it with the defaults "mkfs.btrfs /dev/mapper/somelogicalvolume". Isn't "-m single" the default? So is it right that btrfs "knows" that it is running on a RAID and changes it's behavior? Why? Normally a FS does not care about the underlaying (hidden) disk array. But if it is neccessary to "drop" that duplicate metadata, how can I arrange this afterwards. And if it is done, then I would have reduced the Metadata size, but will there really be more space for Data? Where is the remaining space from 77 GB to 130 GB? Maybe I was pointing it the wrong way, sorry. I created a mdadm software RAID1 and on that is a LVM. I did not use btrfs to span over two disks. The md RAID with LVS was there before and I couldn't change this. This is why I have no btrfs-RAID but a md-RAID. Marcel