From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Anopolsky Subject: Re: snapshot merging? Date: Wed, 24 Sep 2008 02:54:16 -0600 Message-ID: <1222246456.26395.16.camel@telesto> References: <48D63C8E.2060802@wpkg.org> <48D657DB.7050601@oracle.com> <48D65ACD.7030907@wpkg.org> <200809232034.21750.phillips@phunq.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-rBoVL2SZcrViBSP+2Qxk" Cc: Tomasz Chmielewski , Zheng Yan , linux-btrfs@vger.kernel.org To: Daniel Phillips Return-path: In-Reply-To: <200809232034.21750.phillips@phunq.net> List-ID: --=-rBoVL2SZcrViBSP+2Qxk Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Tue, 2008-09-23 at 20:34 -0700, Daniel Phillips wrote: > On Sunday 21 September 2008 07:31, Tomasz Chmielewski wrote: > > > Writeable snapshot has been available in btrfs for a long time. > >=20 > > Writeable snapshots and snapshot merging are two different things. >=20 > I think what Mikulas really means by "snapshot merging" is what we call > "revert to snapshot" in ddsnap (google Zumastor ddsnap). The latter is > more appropriate terminology IMHO. For a snapshotted volume, this just > requires copying any blocks that belong to the snapshot and not the > origin back to the origin. Similarly, one could revert any snapshot > "back" (quotes because there is not necessarily any relationship in > time) to any other. For a filesystem it will not be nearly so simple, > because at best only part of the job can be done at the physical block > level. It took me a while to get what was meant by snapshot merging. Consider this a vote for the "revert" terminology. :) Although, it calls into question some of my assumptions about what people use snapshots for. What do people use snapshots for? Cheers, Eric --=-rBoVL2SZcrViBSP+2Qxk Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQBI2gA4e2L37HVup3ARAqMJAJ9OZqKkq5Cb/3T49Rr7g0rznvuBuQCfYEEA aX/c/9I3Cuvvp2LDKwxCayw= =ctcb -----END PGP SIGNATURE----- --=-rBoVL2SZcrViBSP+2Qxk--