Category Archives: Linux

How to access data from a headless m1730 DELL with broken graphics card

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dem17ll30I have one of those DELL XPS M1730 ‘s with a fried Nvidia graphics card. It still booted, but I obviously couldn’t do much, as the screen was not functioning.

These were the steps I took to access the data:

I downloaded rescuecd pld-linux , a linux live cd that has a SSH Server enabled : http://rescuecd.pld-linux.org/ and burned it to a CD.


download from here : http://rescuecd.pld-linux.org/

Then I booted the XPS from that CD. It didn’t boot right away. As I couldn’t see what was on the screen, I could only guess what it said. But pressing ESC a few time worked for me. If your laptop’s BIOS is not configured to boot from CD, you can press F12 and then one down + enter (you can’t see anything, so try to guess what order the entries in the boot menu are. Normally “CD boot” is the second entry.).

Once booted, I logged in from another PC using SSH. On windows you can use PUTY for that: http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
Login using ‘root’ and password ‘pld’.

pld-screen

I wasn’t able to access the drive, cause it’s RAID0 and (in my case) wasn’t set up. To set up raid I first loaded a config into the mdadm.conf using the mdadm utility used to manage and monitor software RAID devices.

I then rebooted the PC.

After it rebooted, I looked for available drives using lsblk

I examined sdb, and it seemed to be part of a raid setup:

I scanned for the array:

Now I had a new layout for the drives, as the Array came online:

Finally mounted the drive:

To get the data of, you can either use SSH or (if on windows) use WinSCP. You can donwload it here: https://winscp.net. Start WinSCP, Create a new site, fill in IP address, login and password, and connect.

wscp

Check out the man pages of the tools used:

Mdadm : https://linux.die.net/man/8/mdadm
Lsblk : https://linux.die.net/man/8/lsblk
Blkid : https://linux.die.net/man/8/blkid
Mdadm cheat Sheet : http://www.ducea.com/2009/03/08/mdadm-cheat-sheet/

Hopefully this log will help anyone. You can leave comments if you like, but I’m not experienced with mdadm. I probably can’t answers questions, but maybe other readers can. 🙂

Summary:

  1. write the config using mdadm -Es
  2. mount the array, using mount.
  3. Connect using WinSCP and recover the files

vSphere service console read only fstab

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If you “fstabbed” yourself on a guest operating system ( CentOS 6.3 ) running in VMware, you might be in for a surprise. After you edited the fstab ( and introduced an error ) the system won’t boot anymore.

This is the setup: A host OS that is running VMware. Two guest OS’s, on CentOS 5.3 and a CentOs 6.3
One of which I am in the process of preparing to be used with ISPConfig3. While doing that, I had to edit the fstab file. I reluctantly did that, but it later showed that the entry I put there was wrong. After a reboot of the guest OS it didn’t come back. To gain access I had to use vSphere to connect to the host. In vSphere Home->Inventory->Hosts and Clusters, I could reset the guest. Of course it didn’t boot. So I right clicked on the guest and opened the Console. This is a service console what mimics a screen. Another reset and I could see the GRUB options and the system boot. This ended in an error. I could choose between CTRL-D to continue, or enter my root password. I entered the password. Now I had access to the file system. But when I tried to edit the /etc/fstab file, it threw me an error, saying the files sytem was read-only, so I could not save the changes.

After some searching I found this page:
Bypassing Bad fstab Failure While Booting Linux

I did none of what it says, but only used this command in the service console:

Now I could open /ect/fstab for editing and I could save it. Reboot and the server was back in the air.

Hope this helps someone, because it took me a while to find out. 😛

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