From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 79490 invoked by alias); 23 May 2016 15:35:34 -0000 Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Received: (qmail 79478 invoked by uid 89); 23 May 2016 15:35:33 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.3 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=company, meet, commercial, wish X-HELO: mail-wm0-f46.google.com Received: from mail-wm0-f46.google.com (HELO mail-wm0-f46.google.com) (74.125.82.46) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Mon, 23 May 2016 15:35:32 +0000 Received: by mail-wm0-f46.google.com with SMTP id n129so85479291wmn.1 for ; Mon, 23 May 2016 08:35:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=HcSbMbuYkIwwceN4a5H2j51eXxCS4UDeO4Rl5EyeIE0=; b=LOuWIYqbuk3slY0ZxvDytIPWOOKN3bOwfTl4UJoGBzuYOD45x44GPACY8qEbezd+ch Prf8q3vWcO+YJdMzK6fbCEhZ8k4Dl5gZKXx6+i6KLh3ypK4OTRzYGj6MX52BWRdyw/PG PdeHEp1N6lz8Sxwk0z8QZfaKv9TgG3dPBZiOssdLP0b/IgJacXEq4VZACIukiOg2G+/A TkcAt2TeOP5AWGpXrxo6BgzJpg7AM/FXRGIxB4gw+MKWq38IYLuVzBkjyPNdEbXNsErZ CZ6wTBcD7hqNRgcv1Dma7GyczuQDxW51jc3nbbqZRqg1x5nx4f1gOYC6tsjuJib+9JO4 Zgbw== X-Gm-Message-State: ALyK8tLGJqtu/+Yhc67Wl/xIugkui6WOyz7/Sbajcx1GrgNaxBktY3Fs/jeLz534zpvqAg== X-Received: by 10.28.230.87 with SMTP id d84mr14238946wmh.50.1464017729940; Mon, 23 May 2016 08:35:29 -0700 (PDT) Received: from [172.21.188.188] ([149.6.156.42]) by smtp.googlemail.com with ESMTPSA id on2sm35947738wjc.32.2016.05.23.08.35.28 for (version=TLSv1/SSLv3 cipher=OTHER); Mon, 23 May 2016 08:35:29 -0700 (PDT) Subject: =?UTF-8?Q?Re:_tar_incremental_backups_and_ctime=e2=80=8f_problem?= To: cygwin@cygwin.com References: <9fdf98cf-e3d1-e453-1c98-2c206afe81c9@gmail.com> <09f604cd-61df-e0c7-b313-1dcf1ef59b4e@gmail.com> <574313B3.3090703@redhat.com> From: Marco Atzeri Message-ID: Date: Mon, 23 May 2016 15:35:00 -0000 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.1.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2016-05/txt/msg00269.txt.bz2 On 23/05/2016 16:57, x y wrote: >> mtime is fakeable, ctime is not. Using only mtime makes it likely that >> your incremental backup will miss files. I don't have any good reason >> to differ from upstream behavior here. > > Hi Eric, > > The problem is not faking time stamps. Even commercial Windows backup > programs are checking the modification time to identify the modified > files. > > Consider that you have a lot of files opened and closed without any > modification in your company. Because of the priority of the ctime > time stamp, reintroducing all of those files to the incremental backup > does not make any sense. tar has also the capacity to create > differential backups with the condition of taking care of the snapshot > file. The ctime issue can result in unnecessarily big differential > backups filled with unmodified files. > > Cygwin tar can be a good alternative for Windows users to do > differential \ incremental backups but the ctime problem must be > solved. > It is always possible to create file list with find and use that to tar whatever using --files-from=FILE option I don't see the need to change tar behaviour to meet your wish. Regards Marco -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple