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Hi Edward,<br>
<br>
Being able to access a raw hard drive in a vm could be useful whether
you're running Windows, Linux, or Mac. The procedures would be very
similar, and this could serve as a starting point for figuring out how
to do this on those other systems. Not only that, many on this list
are required to work with Windows systems as part of their duties. The
message was labeled with [OT] after all. I'm sure some in the audience
will find the information useful, if for no other reason than as a
jumping off point to do research as to how to implement similar things
on other systems.<br>
<br>
Sincerely,<br>
<br>
Ron<br>
<br>
<br>
On 5/27/2013 9:44 PM, Edward Holcroft wrote:
<blockquote
cite="mid:CAN8XfE_rqOY4NWW4_4Yf4WjYHdNVCgm9Gk3OGns5eg+B6a=W-A@mail.gmail.com"
type="cite">
<div dir="ltr">
<div class="gmail_default" style="font-size: small;">Can someone
explain to me wtf I would subscribe to a Linux list to get these
incessant Windows tips? </div>
<div class="gmail_default" style="font-size: small;"><br>
</div>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Sun, May 26, 2013 at 6:57 PM, Ron Frazier
(ALE) <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:atllinuxenthinfo@techstarship.com" target="_blank">atllinuxenthinfo@techstarship.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">Hi
all,<br>
<br>
I wanted to share the results of an interesting experiment that I'm
doing.<br>
<br>
I'm upgrading a hard drive and wanted to run exhaustive spinrite
testing on it before putting it into service. Normally, this requires
booting the computer from the spinrite cd and giving it total control
over the pc and the hdd so the diagnostic can run. I didn't like the
idea of giving up the use of this pc for 3-4 days to analyze this 1TB
drive. I had heard that you can run spinrite in a vm if you're careful.
Based on a mention of it on Steve's podcast, I found the instructions
and I've got it working. That's the good news. The bad news is that
it's running 4X slower than normal. So, it will take 14 days to process
this drive, but I still have use of my pc, if I keep doing it this way.<br>
<br>
This involves attaching a physical disk drive to virtualbox as though
it was a virtual drive. This is called raw disk access, and it can be
very dangerous. You must make absolutely sure that the vm doesn't
access any drives that your host os is accessing. It's also very
powerful though. Even if you don't want to run spinrite, these
procedures might be useful for other purposes. I did this on windows,
but you could probably do something similar on mac and linux.<br>
<br>
First, you attach the hdd you want to test to a port on your
motherboard. At this point, I don't know how to do this with usb. I
tried to access the usb ports in virtualbox. When I turned on usb 2.0,
it said it needed an extension pack, so I gave up on that. Usb would be
much slower than sata anyway. So, I have the new hdd attached to a sata
port on the mb.<br>
<br>
Next you want to take the disk offline so the host os doesn't do
anything to it. This part is windows centric, so you guys can tell us
how to do this in linux if you know.<br>
<br>
The following page lists the procedure to take the disk offline.<br>
<br>
<a moz-do-not-send="true"
href="http://blog.nerdimmunity.com/2012/06/25/spinrite-vmware-and-windows-7/"
target="_blank">http://blog.nerdimmunity.com/2012/06/25/spinrite-vmware-and-windows-7/</a><br>
<br>
* Run an elevated command prompt (as Administrator), then run
“diskpart”. Once in diskpart, issue these commands.<br>
* list disk<br>
* find the disk you want to work on<br>
* select disk # (Replace "#". In my case select disk 3.)<br>
* list disk (Again. The selected disk should have an asterisk by it.)<br>
* offline disk<br>
* attribute disk clear readonly<br>
* rescan<br>
<br>
You can verify the results by doing a list disk again.<br>
<br>
See this image: <a moz-do-not-send="true"
href="https://dl.dropboxusercontent.com/u/9879631/spinrite-in-vm.png"
target="_blank">https://dl.dropboxusercontent.com/u/9879631/spinrite-in-vm.png</a><br>
<br>
In the upper left is the diskpart screen where I've verified that disk
3 is offline. In the middle left is an image of the Windows disk
administrator which also shows that this disk is offline. Now that you
know the host os won't be messing with the hdd you're working on, you
can use the following procedure to set up your vm and attach it to that
physical disk.<br>
<br>
<a moz-do-not-send="true" href="http://romaimperator.com/?p=29"
target="_blank">http://romaimperator.com/?p=29</a><br>
<br>
Here's a warning from this webpage about raw disk access in a vm. Make
ABSOLUTELY sure you follow the procedure correctly.<br>
<br>
Warning<br>
Raw hard disk access is for expert users only. Incorrect use or use of
an outdated configuration can lead to total loss of data on the
physical disk. Most importantly, do not attempt to boot the partition
with the currently running host operating system in a guest. This will
lead to severe data corruption.<br>
<br>
Once you're done following this procedure, you should have a vmdk file
that is directly linked to the physical hard drive in question.<br>
<br>
In my case, it is srvm-wd1tb-disk3.vmdk .<br>
<br>
So, the name shows what it's doing and which physical disk it's
accessing.<br>
<br>
You then create a vm to run spinrite. I used OS: other / dos and RAM:
32 MB. You do not have to create a virtual disk drive for the vm to
boot from if you boot from a spinrite cd. The upper right of the image
I mentioned shows my virtualbox configuration for this vm. Note that,
in the storage section, I have my hosts CD drive connected, and also
the vmdk file that I mentioned. So, all the storage components the vm
has access to are actual physical drives.<br>
<br>
Once you're done with all that, you boot the vm, which boots from the
CD in the physical drive, since that's first in the boot order.
Spinrite starts up, and the only hard drive it thinks it has access to
is the physical drive you've attached. At this point, you can proceed
to test the drive, albeit very slowly.<br>
<br>
The lower right part of that image shows spinrite running. The lower
left part of the image shows it pegging one of my cpu cores at 100%.<br>
<br>
After spinrite is done, or after you stop its function, power down the
vm. Don't allow spinrite to reboot, which it will try to do if you
press escape at the end.<br>
<br>
Well, that's it. I'm using a program that requires exclusive control of
a hdd, inside a vm, while still using my pc. Very cool. Yes, I know you
can use something like badblocks while linux is running, but that
wasn't my purpose here.<br>
<br>
Misc notes:<br>
<br>
* Do not shut down the host, change the drive cabling, and reboot. This
will change the disk numbering. Even if you just reboot, it would be
wise to check that the disk numbers are the same if you continue prior
activity.<br>
* You can clone the vm to run other copies of spinrite simultaneously.
I think they could all boot from the same cd rom, or you could boot
from an iso. Attach each vm to a different physical drive, which must
also be offline. When you clone the vm, select the box to change all
mac addresses on network adapters, although it may not matter for this
purpose. Also, select a full clone, not a linked clone.<br>
* I found a web page related to doing this on a mac, but have no way to
try it. I haven't tried it on linux either.<br>
<br>
<a moz-do-not-send="true"
href="http://jtsdigs.com/blog/2013/2/3/spinrite-on-a-mac-yes-you-can"
target="_blank">http://jtsdigs.com/blog/2013/2/3/spinrite-on-a-mac-yes-you-can</a><br>
<br>
* Finally, IMPORTANT - when you're done testing the drive and the vm is
powered down, detach the vmdk file pointing to the physical drive from
the vm. Go to the file menu in virtualbox and start the virtual media
manager. DELETE the vmdk file that attached to the physical drive so
you don't accidentally use it again and delete the vmdk file itself if
virtual media manager doesn't do so. Otherwise, you could end up
messing up the next thing you attach to that port on your motherboard.<br>
<br>
Hope you find this interesting and helpful.<br>
<br>
Sincerely,<br>
<br>
Ron<br>
<br>
<br>
</blockquote>
</div>
<br clear="all">
<div><br>
</div>
-- <br>
<div dir="ltr">Edward Holcroft | Madsen Kneppers & Associates Inc.<br>
3020 Holcomb Bridge Rd. NW | Norcross, GA 30071<br>
O (770) 446-9606 | M (678) 587-8649<br>
</div>
</div>
<br>
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</blockquote>
<br>
<pre class="moz-signature" cols="72">--
(PS - If you email me and don't get a quick response, you might want to
call on the phone. I get about 300 emails per day from alternate energy
mailing lists and such. I don't always see new email messages very quickly.)
Ron Frazier
770-205-9422 (O) Leave a message.
linuxdude AT techstarship.com
Litecoin: LZzAJu9rZEWzALxDhAHnWLRvybVAVgwTh3
Bitcoin: 15s3aLVsxm8EuQvT8gUDw3RWqvuY9hPGUU
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