From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Smith Subject: [RFC] dm-userspace Date: Wed, 19 Apr 2006 12:48:55 -0700 Message-ID: <87lku18hy0.fsf@caffeine.beaverton.ibm.com> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1790988502==" Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: device-mapper development List-Id: dm-devel.ids --===============1790988502== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" --=-=-= Content-Transfer-Encoding: quoted-printable Hi List, As you all know, I'm working on a userspace-controlled CoW implementation using device-mapper. The idea is to offer a pseudo device through device-mapper that has CoW behavior, but where the block allocation decisions are made from userspace. My thoughts are that it might be best to abandon the concept of the "dm-cow" target and instead work on a "dm-userspace" target. The userspace cow application I'm working on would remain mostly the same. Similarly, dm-userspace would look almost identical to my dm-cow does right now, but more generic. The target would simply present the details of the data passed to the map() function to userspace, which would respond with a target device and sector of where to send the request. A generic dm-userspace target would allow for testing of new algorithms (RAID, CoW, etc) from a userspace application, as well as some more interesting things involving distributed applications. Just like FUSE allows for some neat (although not necessarily high-performance) tricks, dm-userspace could allow the same thing for block devices. Would the device-mapper maintainers be interested in accepting something like dm-userspace upstream? =2D-=20 Dan Smith IBM Linux Technology Center Open Hypervisor Team email: danms@us.ibm.com --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2.1 (GNU/Linux) iD8DBQBERpQpwtEf7b4GJVQRAq4vAKCJsNr3LDUYUj6eTgWhx9GOz7sc6wCfTg8G dMM+8HWXuEKdBdpcvhEgktI= =XVr0 -----END PGP SIGNATURE----- --=-=-=-- --===============1790988502== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline --===============1790988502==--