Return-Path: Delivered-To: 2-oracle-l@orafaq.com Received: (qmail 3287 invoked from network); 12 Dec 2006 11:32:16 -0600 Received: from freelists-180.iquest.net (HELO turing.freelists.org) (206.53.239.180) by 69.64.49.119 with SMTP; 12 Dec 2006 11:32:15 -0600 Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 2A0D2567CA1; Tue, 12 Dec 2006 12:31:19 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 22291-01-3; Tue, 12 Dec 2006 12:31:19 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 4AF09567C99; Tue, 12 Dec 2006 12:31:17 -0500 (EST) Received: with ECARTIS (v1.0.0; list oracle-l); Tue, 12 Dec 2006 12:30:12 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 0342E567C2F for ; Tue, 12 Dec 2006 12:30:12 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 21826-01 for ; Tue, 12 Dec 2006 12:30:11 -0500 (EST) Received: from mail.pdx.polyserve.com (mail2.pdx.polyserve.com [216.64.170.69]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 6DCE5567635 for ; Tue, 12 Dec 2006 12:30:03 -0500 (EST) Received: from ex2.ms.polyserve.com (ex2.ms.polyserve.com [10.1.0.6]) by mail2.pdx.polyserve.com (Postfix) with ESMTP id 3F51D5EC33A for ; Tue, 12 Dec 2006 09:30:54 -0800 (PST) X-MimeOLE: Produced By Microsoft Exchange V6.5 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C71E13.4611A388" Subject: RE: ZFS snapshots Date: Tue, 12 Dec 2006 09:30:53 -0800 Message-ID: <5D2570CAFC98974F9B6A759D1C74BAD001C3378F@ex2.ms.polyserve.com> In-Reply-To: <248A58C2AB63304C82F0706DE62FB345015AA29D@nyc.kbcfp.com> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: ZFS snapshots From: "Kevin Closson" To: X-archive-position: 43048 X-ecartis-version: Ecartis v1.0.0 Sender: oracle-l-bounce@freelists.org Errors-to: oracle-l-bounce@freelists.org X-original-sender: kevinc@polyserve.com Precedence: normal Reply-to: kevinc@polyserve.com List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: oracle-l X-List-ID: oracle-l List-subscribe: List-owner: List-post: List-archive: X-list: oracle-l X-Virus-Scanned: by amavisd-new-20030616-p10 (Debian) at avenirtech.net ------_=_NextPart_001_01C71E13.4611A388 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable I can only talk about filesystem snapshots that I know. With veritas and the upcoming polyserve snapshots, if all files are in one directory, a snapshot looks EXACTLY like a database that was running on a system where the power was turned on. Exactly. =20 ________________________________ From: oracle-l-bounce@freelists.org [mailto:oracle-l-bounce@freelists.org] On Behalf Of Donahue, Adam Sent: Tuesday, December 12, 2006 6:59 AM To: Kerber, Andrew; oracle-l@freelists.org Subject: RE: ZFS snapshots =09 =09 Well, a ZFS snapshot is atomic - meaning, it's not like copying a datafile in that it doesn't read things block-by-block, meaning the file can change underneath you while you copy it. Instead, because of the way ZFS works, it merely marks an existing "uberblock" to be preserved, which is a single, atomic state of the filesystem as of a given time. =20 I admit it's not clean - even if it works. But I'm curious if I'm missing something that would make it not work at all in some cases. =20 is not indicative of future returns.=20 ------_=_NextPart_001_01C71E13.4611A388 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable ZFS snapshots
I can only talk about filesystem snapshots = that I know.=20 With veritas and the upcoming
polyserve snapshots, if all files are in one = directory,=20 a snapshot looks EXACTLY like a
database that was running on a system where = the power=20 was turned on. Exactly.
 

From: = oracle-l-bounce@freelists.org=20 [mailto:oracle-l-bounce@freelists.org] On Behalf Of Donahue,=20 Adam
Sent: Tuesday, December 12, 2006 6:59 AM
To: = Kerber,=20 Andrew; oracle-l@freelists.org
Subject: RE: ZFS=20 snapshots

Well, a ZFS snapshot is atomic - meaning, it's not like = copying a=20 datafile in that it doesn't read things block-by-block, meaning the = file can=20 change underneath you while you copy it.  Instead, because of the = way ZFS=20 works, it merely marks an existing "uberblock" to be preserved, which = is a=20 single, atomic state of the filesystem as of a given = time.
 
I admit it's not clean - even if it works.  But = I'm=20 curious if I'm missing something that would make it not work at all in = some=20 cases.
 
is not indicative of future returns.=20
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