From owner-freebsd-questions Tue Jan 15 18:24: 7 2002 Delivered-To: freebsd-questions@freebsd.org Received: from mail4.nc.rr.com (fe4.southeast.rr.com [24.93.67.51]) by hub.freebsd.org (Postfix) with ESMTP id 1605037B41A for ; Tue, 15 Jan 2002 18:23:18 -0800 (PST) Received: from there ([66.57.85.154]) by mail4.nc.rr.com with Microsoft SMTPSVC(5.5.1877.687.68); Tue, 15 Jan 2002 21:23:17 -0500 Content-Type: text/plain; charset="iso-8859-1" From: Brian T.Schellenberger To: "Mike Meyer" Subject: Re: HOWTO -- backup onto CDRs? Date: Tue, 15 Jan 2002 21:22:51 -0500 X-Mailer: KMail [version 1.3] Cc: questions@FreeBSD.ORG References: <15426.33499.296182.78699@guru.mired.org> <200201152209.g0FM9eI00811@i8k.babbleon.org> <15428.54969.119254.138926@guru.mired.org> In-Reply-To: <15428.54969.119254.138926@guru.mired.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID: <0a2d11623021012FE4@mail4.nc.rr.com> Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Tuesday 15 January 2002 08:26 pm, Mike Meyer wrote: > Brian T. Schellenberger types: > > > > I did this all the time under Linux; even with a P-450 it worked just > > > > fine as long as the system wasn't overtaxed (as in, load < 2), using > > > > the stdin feature of cdrecord. I tried with burncd under FreeBSD and > > > > had no success, though. Of course, cdrecord doesn't support stdin > > > > input so I > > > > Drat. I meant "Of course, burncd doesn't support stdin . . . ." > > Use /dev/stdin as the file to burn. That works with burncd for me. > > Brian T. Schellenberger types: > > On Tuesday 15 January 2002 02:48 pm, Gary W. Swearingen wrote: > > > Anybody know what FS-specific (dump/restore) and non-FS-specific (tar, > > > cpio, pax, afio) archivers SHOULD do with sockets and named pipes? (Are > > > there any other kind of weird "files" besides those and block- & > > > character-special files and symbolic links?) > > > > Anyway, these are the only types of files that perl knows aobut; looks > > pretty complete to me: > > There's one other type of screwy file: sparse files. These have > "holes" where there are no blocks on disk. You can create one > trivially: > > bash-2.05$ dd if=/dev/zero of=y oseek=1000 count=2 > 2+0 records in > 2+0 records out > 1024 bytes transferred in 0.000059 secs (17353403 bytes/sec) > bash-2.05$ ls -l y > -rw-r--r-- 1 mwm wheel 513024 Jan 15 19:19 y > bash-2.05$ df . > Filesystem 1K-blocks Used Avail Capacity Mounted on > mfs:28 127023 111 116751 0% /tmp > bash-2.05$ rm y > > So I now have a file 513K long that occupies 1K of disk space. In > fact, the file is on a file system that's only 127K in size. > > The nasty part about sparse files is that there is no way to recognize > them as such without examining the file systems internal > structures. For instance: > > bash-2.05$ wc y > 0 1 513024 y > > The system provides a block full of zeros for the blocks that are > missing. Tar tries to recognize them as such. Cpio only does that if > you use the --sparse option. Are these at all common? For the matter, are they preserved by cp? They seem like a hyphothetical concern more than a practical one and a nuisance more than a benefit. But maybe that's just me. Regardless, if you do a compressed backup they should compress real nicely (though not as efficiently as the sparse files), though they will spring to full space on a restore if the backup/restore program isn't clueful about them. > > Free Dmitry Sklyarov! (let him go home) <----------- http://www.eff.org http://www.programming-freedom.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message