From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phillip Susi Subject: Re: Chunk map/control Date: Wed, 10 Nov 2010 10:08:36 -0500 Message-ID: <4CDAB574.2040407@cfl.rr.com> References: <4C9A631D.2030202@cfl.rr.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" To: linux-btrfs@vger.kernel.org Return-path: In-Reply-To: <4C9A631D.2030202@cfl.rr.com> List-ID: On 9/22/2010 4:12 PM, Phillip Susi wrote: > Is there currently a way to view and manipulate the chunks? If I > understand things correctly, a new fs has a few chunks: > > 1) System chunk. Contains tree of trees, device tree, chunk tree. > 2) Metadata chunk. Contains the directory tree for the default subvol, > and any additional subvols/snapshots you create. Directory entries and > inodes are in this tree. > 3) Data chunk. Files with significant data have blocks allocated from > this chunk. > > The system chunk is always mirrored, even on a single disk. The > metadata chunk is mirrored by default, but can be changed with a > parameter to mkfs. The data chunk is striped by default, but can be > changed via parameter to mkfs. The chunks are all expanded as needed. > Is this correct, and is there a way to create a subvol with a new pair > of metadata/data chunks and specify how they should be striped or > mirrored across what devices?