On 02/12/2014 12:47 PM, Bernhard Voelker wrote: > Thanks, I'll prepare a patch for the docs, then.
Here is a proposal. Have a nice day, Berny >From 7f73ea7a32f731baef49b4e8988f0b3c7618a983 Mon Sep 17 00:00:00 2001 From: Bernhard Voelker <[email protected]> Date: Thu, 13 Feb 2014 00:32:48 +0100 Subject: [PATCH] doc: add dd example for failing disks * doc/coreutils.texi (dd invocation): Add an example for how to call dd to save data from a failing disk. Mention GNU 'ddrescue' as one of the more specialized tools in such a case. --- doc/coreutils.texi | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 3269291..e2339f3 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -8927,6 +8927,22 @@ tape=/dev/rmt/0 (dd bs=4k seek=1 count=0 && dd bs=512k) <$tape >$disk @end example +@cindex ddrescue +@cindex disks, failing +For failing disks, other tools come with a great variety of extra +functionality to ease the saving of as much data as possible, e.g. +@uref{http://www.gnu.org/software/ddrescue/, GNU @command{ddrescue}}. +However, in cases where such a tool is not available or when the administrator +feels more comfortable with the handling of @command{dd}, calling it with the +options @samp{iflag=fullblock} to avoid short reads and @samp{conv=sync,noerror} +to pad out unreadable parts and to continue on read errors might be +helpful as well: + +@example +# Rescue data from an (unmounted!) partition of a failing disk. +dd conv=noerror,sync iflag=fullblock </dev/sda1 > /mnt/rescue.img +@end example + Sending an @samp{INFO} signal to a running @command{dd} process makes it print I/O statistics to standard error and then resume copying. In the example below, -- 1.8.4.5
