From owner-freebsd-questions@FreeBSD.ORG Mon Oct 14 22:21:19 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id E1238FB4 for ; Mon, 14 Oct 2013 22:21:19 +0000 (UTC) (envelope-from cswiger@mac.com) Received: from mail-out.apple.com (mail-out.apple.com [17.151.62.51]) (using TLSv1 with cipher RC4-MD5 (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 991D52C55 for ; Mon, 14 Oct 2013 22:21:19 +0000 (UTC) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; CHARSET=US-ASCII Received: from relay2.apple.com ([17.128.113.67]) by mail-out.apple.com (Oracle Communications Messaging Server 7u4-23.01 (7.0.4.23.0) 64bit (built Aug 10 2011)) with ESMTP id <0MUO000HKJEXI0L1@mail-out.apple.com> for freebsd-questions@freebsd.org; Mon, 14 Oct 2013 15:21:13 -0700 (PDT) X-AuditID: 11807143-b7fce6d000001c8e-93-525c6e5980db Received: from [17.153.98.163] (Unknown_Domain [17.153.98.163]) (using TLS with cipher AES128-SHA (128/128 bits)) (Client did not present a certificate) by relay2.apple.com (Apple SCV relay) with SMTP id 30.7C.07310.95E6C525; Mon, 14 Oct 2013 15:21:13 -0700 (PDT) Subject: Re: SU+J Lost files after a power failure From: Charles Swiger In-reply-to: <20131014204125.6cc4a31e@gumby.homeunix.com> Date: Mon, 14 Oct 2013 15:21:17 -0700 Message-id: <89DF80F4-E426-4457-BDBF-958B1CBDB52F@mac.com> References: <525A6831.5070402@gmail.com> <20131014133953.58f74659@gumby.homeunix.com> <525C1D1C.9050708@gmail.com> <525C2554.7080203@pchotshots.com> <525C2FBC.4080808@cran.org.uk> <20131014204125.6cc4a31e@gumby.homeunix.com> To: RW X-Mailer: Apple Mail (2.1510) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrALMWRmVeSWpSXmKPExsUiODNpsW5kXkyQwd85uhYvv25isVh6azOL A5PHjE/zWTyeTpjMHsAUxWWTkpqTWZZapG+XwJXx6GMTS8EXzoor8zUbGF+xdzFyckgImEhc eTOHCcIWk7hwbz1bFyMXh5BAL5PErid9LCAJZgEtiRv/XgIVcXDwCuhJbP8lBxIWFjCSuLJn BStImE1ATWLCRB6QMKeApcTfY3vAOlkEVCXeT5vLDDFFUWJH2xqoifIS29/OAYvzClhJPDm1 mwVi7QEWieMrpoPdJiKgLDGvdzkbxG2yEqfPPWeZwMg/C8lFsxAumoVk7AJG5lWMAkWpOYmV RnqJBQU5qXrJ+bmbGEHh1lDovIPx2DKrQ4wCHIxKPLw/eGOChFgTy4orcw8xSnAwK4nw5r6N DhLiTUmsrEotyo8vKs1JLT7EKM3BoiTOu8YLqFogPbEkNTs1tSC1CCbLxMEp1cDoedhE5Eyt u/Ye95DVey9KMf7+/qj4cX6stlmVZ3TS3lUq3+zefdwuGT6hYOPSHK56G85d814kTvm/9blP b2XYSvMmLtNjXfKTg/81Pngdo7TQdqepY8e8+yaKU1y85vQY3p4aoLNw8r7NDNo+8cfKYrqT bqh97iqW3bHUqOsS61TPPn3nS9OUWIozEg21mIuKEwFIcKZ8MwIAAA== Cc: freebsd-questions@freebsd.org X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 14 Oct 2013 22:21:19 -0000 On Oct 14, 2013, at 12:41 PM, RW wrote: > On Mon, 14 Oct 2013 11:48:18 -0700 Charles Swiger wrote: >> Yes. Without journalling, you'd normally perform the full >> timeconsuming fsck in the foreground. > > Journalling removes the need for the background fsck which only recovers > lost space. That and inode link changes (ie, adding or removing files from a directory). >> With journalling, it should be able to do a journal replay to restore >> the filesystem to an OK state, > > My understanding is that the journal does nothing to restore the > filesystem other than keep track of orphaned memory. In all other > respect it's the job of soft-updates to keep the filesystem in an OK > state. Yes, SU is supposed to reorder filesystem operations to provide some level of "ACID" transaction semantics-- and the journal helps that by avoiding the need for bgfsck. > When it doesn't you need a foreground check. > >> but sometimes that doesn't restore consistency, in which case it >> usually fires off a background fsck rather than the foreground fsck. > > I think if the journal fails, you would really need to run at least a > foreground preen, maybe a full fsck. Yes. Regards, -- -Chuck