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Topic: Looking for suggestions, Readying PC's for kids

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cbagger01

Group: Members
Posts: 4264
Joined: Oct. 2003

Posted: July 23 2004,02:00

FYI,

If you are going to do a compressed raw image 'dd' backup, before you begin the backup you should overwrite all of the free disk space on your "perfect PC" partition with a bunch of zeros, instead of the random data that is currently saved inside your unused sectors.

One way of doing this is to type something like:

dd if=/dev/zero of=/home/username/file_of_zeros.bin bs=1M

this will create a big file of zeros in your home directory. The file will stop growing when there is no space left on the disk. Then you should delete the file with:

rm /home/username/file_of_zeros.bin

One of the advantages of using a live Linux distribution for network image backups is:

(1) You can use 100Mbps network speed if available and your card supports this.
(2) Linux ide kernel supports DMA acceleration which speeds up hard drive access.
(3) Because the 'dd' backup is a raw backup tool, you can grab any type of disk partition, including future filesystems that have not been invented yet like EXT5, Microsoft Windows 2012 NTFS7, reiserFS 6.0, etc. Tools like "Ghost" or "DriveImage" or "partimage" that learn the filesystem type and only copy the in-use sectors quickly become obsolete beause the filesystem types change with every next generation OS and they are incompatible with future filesystems.

These features are not always true for the old MSDOS based imaging utility programs.

On a lowly 10Mbps network, with compression I was able to back up a 3GB partition (full) in about 25 minutes.

ke4nt1

Group: Members
Posts: 2329
Joined: Oct. 2003

Posted: July 23 2004,05:37

cbagger.....
Wow !!

Everytime you explain things in detail like your last post, it truly feeds my head.

The " file_of_zeros.bin" would be exceptionally useful for old hard drives that
will find new homes in others boxes and systems. I can't tell you the number of
hard drives I have purchased, either loose or in a machine, that are full of stuff.
I choose to at least format the drive, but who am I foolin, my grandma?

Your list of advantages to using a linux liveCD for network backups is
some powerful medicine.. Where can I locate more details on these methods ?

I have many systems on several networks, which I am responsible for keeping
intact, bug free, and archived. ( I know,.. rotsa ruck )
I have been backing up data over 100baseT to DVD-R.
Bare metal backups only locally direct-to-DVD-R - no network capability.

Very few packages will do this natively.
Most require some third party "packet writer" plugin or UDF filesystem app. ........."yuck"..........

I also backup audio/video CD/DAT/DVD masters and data to DLT, mostly
for pressing/replication masters, but again, no bare metal backups....

Got any ideas for taking the ideas from your last post, and being able to
get from backup to bare metal for full restores? ( or visa-versa? )
Of course, these are mostly NTFS/winXP/win2K systems with large drives
for editing and producing multimedia, DVD content, and Music CD masters.

73 de Kent
ke4nt

cbagger01

Group: Members
Posts: 4264
Joined: Oct. 2003

Posted: July 23 2004,12:00

If you are going to do a RAW backup of a Windows NTFS partition, you should do the equivalent of the "file of zeros" trick on this drive. Since you can't write to an NTFS partition with the standard Linux NTFS driver, you should use a command line utility like "zapfree" to do this from the computer while it is booted up under Windows. See this link for details:

http://www.virweb.com/wintools.htm

If you wish to break your image backups into manageable chunks, you can pipe the output through the "split" utility.

See the following example of backing up a TIVO hard disk in Linux for more details:

http://tivo.samba.org/index.cgi?req=edit&file=faq02.018.htp

If you want to be able to restore your backups directly from the DVD drive (no networks), all of the files need to be saved to a temporary hard drive location so that they can be "cat"-ed back together into one file.

However, if you don't use gzip compression you can restore them directly from the DVD or CD drive one at a time with a sequence of commands that work something like this:

cat /mnt/cdrom/file.aa | dd of=/dev/hda count=650M

<removes first disk and inserts second disk and mounts it>

cat /mnt/cdrom/file.ab | dd of=/dev/hda count=650M skip=650M

< removes second disk and inserts third disk and mounts it>

cat /mnt/cdrom/file.ac | dd of=/dev/hda count=650M skip=1300M

etc...

I probably am giving you a bad example of the syntax of the "dd" command, but you should get the general idea that I am trying to convey. I don't remember if you can specify the dd size and the dd skip commands with human readable values like "650M" but the overall concept is still valid.

Oh yeah, I almost forgot: If you are restoring a Windows computer that is part of a corporate WINDOWS NT DOMAIN and the image backup is old, you will need to get the PC to rejoin the domain. This is true regardless of the image backup program (Ghost, Driveimage, Partimage, 'dd' command, etc).

hasty

Group: Members
Posts: 280
Joined: Oct. 2003

Posted: July 23 2004,19:18

Chris
As an addendum have a look for a free CD called the ultimate boot disk at http://www.ultimatebootcd.com/

This has a load of hard disk utilities from the major hard driver makers allowing you to test format/low level format etc., as well a lots of other file stuff. Saved my bacon on a number of occasions when things didn't go according to plan (eg neither linux or win would look at a drive).
hth.