10-14-2004
Software Raid - changed devices
Good Morning all,
I just have a quick question, on some systems I am working with Software Raid Level 0 devices.
Yes, I know, this is not a good idea, but it was requested :-(
Now, due to a new requirement, I need to add a second internal disk to the system, but with adding the new disk, all device links of the external disks, /dev/sdg ..., will move one step further.
I tried this on a test system, modified the /etc/raidtab and when I started the raid device, I got the error message that not all devices were aviable.
I check a bit the configuration and the raid configuration itself looks like it is also written to the Superblock of each physical raid device.... and not only to /etc/raidtab ?
Now, I am lookig for a decent solution how to change the raid configuration, I could recreat the raid system after backing up the data, but this I would like to avoid because of time which is needed for it.
I also could fix the counting order of the currently used disk, so the new added disk would start behind the last currently used disk, but this is some kind of special hack, I also would like to avoid ...
Any ideas ?
Btw, I am running RedHat AS 2.1 on a multiprozessor system.
Thnx in advance
Malcom
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SFILL(1) General Commands Manual SFILL(1)
NAME
sfill - secure free disk and inode space wiper (secure_deletion toolkit)
SYNOPSIS
sfill [-f] [-i] [-I] [-l] [-l] [-v] [-z] directory/mountpoint
DESCRIPTION
sfill is designed to delete data which lies on available diskspace on mediums in a secure manner which can not be recovered by thiefs, law
enforcement or other threats. The wipe algorythm is based on the paper "Secure Deletion of Data from Magnetic and Solid-State Memory" pre-
sented at the 6th Usenix Security Symposium by Peter Gutmann, one of the leading civilian cryptographers.
The secure data deletion process of sfill goes like this:
* 1 pass with 0xff
* 5 random passes. /dev/urandom is used for a secure RNG if available.
* 27 passes with special values defined by Peter Gutmann.
* 5 random passes. /dev/urandom is used for a secure RNG if available.
afterwards as many temporary files as possible are generated to wipe the free inode space. After no more temporary files can be created,
they are removed and sfill is finnished.
COMMANDLINE OPTIONS
-f fast (and insecure mode): no /dev/urandom, no synchronize mode.
-i wipe only free inode space, not free disk space
-I wipe only free disk space, not free inode space
-l lessens the security. Only two passes are written: one mode with 0xff and a final mode with random values.
-l -l for a second time lessons the security even more: only one random pass is written.
-v verbose mode
-z wipes the last write with zeros instead of random data
directory/mountpoint this is the location of the file created in your filesystem. It should lie on the partition you want to write.
LIMITATIONS
FILESYSTEM INTELLIGENCE
Most filesystems (ext2, ffs, etc.) have several features included to enhance performance, which will result in that sfill might not
receive all available free space. Sad but true. Nothing can be done about that ...
NFS Beware of NFS. You can't ensure you really completely wiped your data from the remote disks. (especially because of caching)
Raid Raid Systems use stripped disks and have got large caches. It's hard to wipe them.
swap Some of your data might have a copy in your swapspace. sswap is available for this task.
BUGS
No bugs. There was never a bug in the secure_deletion package (in contrast to my other tools, whew, good luck ;-) Send me any that you
find. Patches are nice too :)
AUTHOR
van Hauser / THC <vh@thc.org>
DISTRIBUTION
The newest version of the secure_deletion package can be obtained from http://www.thc.org
sfill and the secure_deletion package is (C) 1997-2003 by van Hauser / THC (vh@thc.org)
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
the Free Software Foundation; Version 2.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MER-
CHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
SEE ALSO
srm (1), sswap (1), sdmem (1)
SFILL(1)