From owner-freebsd-current@FreeBSD.ORG Wed Jun 10 05:50:15 2009 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DF50B1065676 for ; Wed, 10 Jun 2009 05:50:15 +0000 (UTC) (envelope-from oberman@es.net) Received: from mailgw.es.net (mail3.es.net [IPv6:2001:400:4c01::2]) by mx1.freebsd.org (Postfix) with ESMTP id ACC7A8FC08 for ; Wed, 10 Jun 2009 05:50:15 +0000 (UTC) (envelope-from oberman@es.net) Received: from ptavv.es.net (ptavv.es.net [IPv6:2001:400:910::29]) by mailgw.es.net (8.14.3/8.14.3) with ESMTP id n5A5oETp015618 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Tue, 9 Jun 2009 22:50:14 -0700 Received: from ptavv.es.net (ptavv.es.net [127.0.0.1]) by ptavv.es.net (Tachyon Server) with ESMTP id 001C71CC0D; Tue, 9 Jun 2009 22:50:13 -0700 (PDT) To: Wojciech Puchar In-reply-to: Your message of "Tue, 09 Jun 2009 19:32:30 +0200." Date: Tue, 09 Jun 2009 22:50:13 -0700 From: "Kevin Oberman" Message-Id: <20090610055014.001C71CC0D@ptavv.es.net> X-Proofpoint-Virus-Version: vendor=fsecure engine=1.12.8161:2.4.5, 1.2.40, 4.0.166 definitions=2009-06-10_03:2009-06-01, 2009-06-10, 2009-06-08 signatures=0 Cc: freebsd-current@freebsd.org, Dan Naumov Subject: Re: sysinstall, GJOURNAL and ZFS X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 10 Jun 2009 05:50:16 -0000 > Date: Tue, 9 Jun 2009 19:32:30 +0200 (CEST) > From: Wojciech Puchar > Sender: owner-freebsd-current@freebsd.org > > >> UFS2+SoftUpdates works fine on properly configured UFS2 - and very fast. > > Yes, UFS2+SoftUpdates is very fast, however, in the case of a power > > loss or having to pull the plug on a locked up system, it has a > > noticeably higher chance of leaving you with an unbootable system than > > can you please give an example how it may render unbootable system? > > For what i know and ever used (ext2,ext3,reiserfs,rarely NTFS, UFS) > UFS is the only one that never failed. It is always recoverable, with few > lost files worst case. > > I recommend you to read a paper about softupdates to understand why they > are so good. > > The only problem with millions of files may be long fsck. but not THAT > long, and FreeBSD doesn't crash every day. Not quite true. The problem is not soft updates. It is write cache on many cheaper hard drives. While soft updates orders write to the hard drive so that the only thing that you can lose is recently written files, but soft updates depends on the data actually being written in the proper sequence and SCSI disks and some ATA drives do this correctly, but many don't and provide on tool to be really sure that they have. Of course, write cache can be disabled on ATA drives and that will make soft updates safe, but the performance hit can be huge. -- R. Kevin Oberman, Network Engineer Energy Sciences Network (ESnet) Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab) E-mail: oberman@es.net Phone: +1 510 486-8634 Key fingerprint:059B 2DDF 031C 9BA3 14A4 EADA 927D EBB3 987B 3751