From 0451e1c23a556fd7bee67b5646f77d8c08a069dd Mon Sep 17 00:00:00 2001 From: Arno Wagner Date: Sat, 29 Dec 2012 12:44:40 +0100 Subject: [PATCH] Added wipefs as option for fast FS removal in section 2.1 --- FAQ | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/FAQ b/FAQ index 3d00b567..f1068ff2 100644 --- a/FAQ +++ b/FAQ @@ -227,23 +227,27 @@ A. Contributors loop-file. 03) If the target was in use previously, it is a good idea to - wipe it before creating the LUKS container, in order to remove any - trace of old file systems, etc. For example, some users have + wipe it before creating the LUKS container in order to remove any + trace of old file systems and data. For example, some users have managed to run e2fsck on a partition containing a LUKS container, possibly because of residual ext2 superblocks from an earlier use. This can do arbitrary damage up to complete and permanent loss of all data in the LUKS container. - To wipe, use something like + To just quickly wipe file systems (old data may remain), use - cat /dev/zero > target + wipefs -a + + To wipe file system and data, use something like + + cat /dev/zero > This can take a while. To get a progress indicator, you can use the tool dd_rescue (->google) instead or use my stream meter "wcs" (source here: http://www.tansi.org/tools/index.html) in the following fashion: - cat /dev/zero | wcs > target + cat /dev/zero | wcs > Be very sure you have the right target, all data will be lost! @@ -251,14 +255,14 @@ A. Contributors at some time in the future this will become unnecessary. 04) Create the LUKS container: - cryptsetup luksFormat target + cryptsetup luksFormat Just follow the on-screen instructions. 05) Map the container. Here it will be mapped to /dev/mapper/c1: - cryptsetup luksOpen target c1 + cryptsetup luksOpen c1 - 06) (Optionally) wipe the container + 06) (Optionally) wipe the container (make sure you have the right target!): cat /dev/zero > /dev/mapper/c1 Note that this creates a small information leak, as an attacker can