Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Linux - Restoring Backup with DD & Netcat - Can't write to /dev/sda device

Posted on 2008-06-11
3
Medium Priority
?
805 Views
Last Modified: 2013-12-16
Disclaimer: /dev/sda is not mounted (It wasn't mounted when I backed it up, and it isn't mounted now that I'm trying to restore the backup)

Hi, i made a backup of my hard drive a month ago with:

dd if=/dev/sda | nc IP PORT

Now, I need to restore my backup, so I'm doing:

nc -l -p 1234 | dd of=/dev/sda

My sender computer is sending, but the receiver isn't doing much of any receiving... It appears that roughly 16 megs are being sent, but none received - In fact, when I hit Ctrl-C, i get the message:

write(stdout): Interrupted System Call

and then my terminal is locked up.

I've attempted to run Ubuntu 7 Live CD & Trinity Rescue CD Build 318 -- both operating systems encounter the exact same problem.

It's possible that my hard drive is broken, but I think it's fine

Any tips on writing directly to /dev/sda without mounting?

Thanks
0
Comment
Question by:oxygen_728
  • 2
3 Comments
 
LVL 2

Expert Comment

by:dualarrow
ID: 21766255
Hi

The nc man pages state

 -p source_port
             Specifies the source port nc should use, subject to privilege
             restrictions and availability.  It is an error to use this option
             in conjunction with the -l option.

One of their examples is

    nc -l 1234

I tried with your example of "nc -l -p 1234" and it comes up immediately with usage instructions.

It looks like you should not be specifying the -p option. Just try

  nc -l 1234 | dd of=/dev/sda

I haven't used the dd command so I cant vouch for the rest of the command but it seems you have the wrong syntax for the nc command.

Andrew
0
 

Author Comment

by:oxygen_728
ID: 21769864
Dual,

In the debian flavor of Linux, i've been using nc -l -p 1234.  A single -l flag indicates "listen mode" and -p #### specifies the port.

Regardless, I did test the command that you suggested. This resulted in all incoming connections being rejected.


0
 

Accepted Solution

by:
oxygen_728 earned 0 total points
ID: 21771732
See this post for a detailed answer:
http://www.experts-exchange.com/OS/Linux/Q_23479648.html

Basically, my hard-drive was broken and it should be a simple matter to write directly to a drive such as /dev/sda with dd

0

Featured Post

Learn Veeam advantages over legacy backup

Every day, more and more legacy backup customers switch to Veeam. Technologies designed for the client-server era cannot restore any IT service running in the hybrid cloud within seconds. Learn top Veeam advantages over legacy backup and get Veeam for the price of your renewal

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Using 'screen' for session sharing, The Simple Edition Step 1: user starts session with command: screen Step 2: other user (logged in with same user account) connects with command: screen -x Done. Both users are connected to the same CLI sessio…
In the first part of this tutorial we will cover the prerequisites for installing SQL Server vNext on Linux.
Learn how to get help with Linux/Unix bash shell commands. Use help to read help documents for built in bash shell commands.: Use man to interface with the online reference manuals for shell commands.: Use man to search man pages for unknown command…
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.
Suggested Courses
Course of the Month11 days, 8 hours left to enroll

916 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question