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AIX
How to use dd command to erase the data in disk
Post 302475152 by Corona688 on Friday 26th of November 2010 05:47:37 PM
11-26-2010
Shredding perfectly good disks is a waste of hardware and probably a warranty violation. 
I vaguely remember a warranty disagreement between Dell and the US military... They could hardly return the machines intact after they'd used them. They came to a rather Pyrrhic compromise: Dell got the drives back, but didn't get their platters!
It of course depends on your security standards but a simple dd if=/dev/zero of=/dev/disk will wreck the data badly enough that you'd need to hire cleanroom spacesuit people and their special machine to have any hope of retrieving it. With 7 overwrites, not even that.
The shred utility I mentioned earlier does that kind of destructive overwrite at the file level, on filesystems that support it, letting you securely delete a file without needing to reformat. Of course that's no guarantee there's nothing unwanted in unlinked sectors somewhere.
I vaguely remember a warranty disagreement between Dell and the US military... They could hardly return the machines intact after they'd used them. They came to a rather Pyrrhic compromise: Dell got the drives back, but didn't get their platters!It of course depends on your security standards but a simple dd if=/dev/zero of=/dev/disk will wreck the data badly enough that you'd need to hire cleanroom spacesuit people and their special machine to have any hope of retrieving it. With 7 overwrites, not even that.
The shred utility I mentioned earlier does that kind of destructive overwrite at the file level, on filesystems that support it, letting you securely delete a file without needing to reformat. Of course that's no guarantee there's nothing unwanted in unlinked sectors somewhere.
Last edited by Corona688; 11-27-2010 at 02:09 AM.. Reason: /dev/zero, not /dev/null
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LEARN ABOUT DEBIAN
mfi
MFI(4) BSD Kernel Interfaces Manual MFI(4) NAME
mfi -- LSI MegaRAID SAS driver SYNOPSIS
To compile this driver into the kernel, place the following lines in your kernel configuration file: device pci device mfi Alternatively, to load the driver as a module at boot time, place the following line in loader.conf(5): mfi_load="YES" DESCRIPTION
This driver is for LSI's next generation PCI Express SAS RAID controllers. Access to RAID arrays (logical disks) from this driver is pro- vided via /dev/mfid? device nodes. A simple management interface is also provided on a per-controller basis via the /dev/mfi? device node. The mfi name is derived from the phrase "MegaRAID Firmware Interface", which is substantially different than the old "MegaRAID" interface and thus requires a new driver. Older SCSI and SATA MegaRAID cards are supported by amr(4) and will not work with this driver. Two sysctls are provided to tune the mfi driver's behavior when a request is made to remove a mounted volume. By default the driver will disallow any requests to remove a mounted volume. If the sysctl dev.mfi.%d.delete_busy_volumes is set to 1, then the driver will allow mounted volumes to be removed. HARDWARE
The mfi driver supports the following hardware: o LSI MegaRAID SAS 1078 o LSI MegaRAID SAS 8408E o LSI MegaRAID SAS 8480E o LSI MegaRAID SAS 9260 o Dell PERC5 o Dell PERC6 o IBM ServeRAID M5015 SAS/SATA o IBM ServeRAID-MR10i o Intel RAID Controller SROMBSAS18E FILES
/dev/mfid? array/logical disk interface /dev/mfi? management interface DIAGNOSTICS
mfid%d: Unable to delete busy device An attempt was made to remove a mounted volume. SEE ALSO
amr(4), pci(4), mfiutil(8) HISTORY
The mfi driver first appeared in FreeBSD 6.1. AUTHORS
The mfi driver and this manual page were written by Scott Long <scottl@FreeBSD.org>. BUGS
The driver does not support big-endian architectures at this time. BSD
May 12, 2010 BSD