Mini HOWTOS.

You will, not might, need this at some point in time. It will happen to you. When you find that grub2 is no longer on your MBR so the system will not boot or even find grub. For example you installed Windows, dumb move, but heh! You may also have cloned the hard disk and forgot to copy the MBR.

You will need an Ubuntu LIVE cd, Desktop for your current install. Boot the system with Live cd. Once booted open a terminal.

Mount the partition that has your root directory in it, my the case above that would be /dev/sda1. mount it directly in /mnt as we will chroot it later. You also need to /dev/and /proc to their subdirectories in /mnt. If you have a separate /boot partition then mount that too, as /mnt/boot

We can now create a chroot environment at /mnt and then proceed to install grub2.

After chrooting, you we will have changed user to root so not need to sudo.

Now we are ready to install/reinstall Grub2.

If you get errors with that command try running the next command too

Make sure to rebuild the menus with the new disk info

Now you can exit the chroot, umount the system and reboot your with your shiny new grub2 install

Ok, so you have a working VBox machine and you want to run it on a host server, This allows you to connect to it remotely. Until VBoxWeb get written here is a quick and dirty way.

To make the remote connect a little more secure you can stop any old person connecting in with out authentication by configuring vrdp port and vrdpauthtype. By using the auth type of external only users who can be verified by the host server can connect using rdesktop. They can still connect via other methods if setup in the guest such as ssh or VNC.

First we will set the port to 5001 and turn on authtype external.

To run the VBox guest on the host you need a coomand line similar to the following. The output below is what you would see if you ran it in a terminal and then later stopped the guest.

The following can be setup in the rc.local so that the gest will automatically restart when the host is rebooted.

Change "vboxuser" to any user you want to run the server. To connect to the VBox guest via rdesktop the following works for me.

The filesytem should not be mounted.

Stop the array allowing us to remove thew array.

Remove the marker from the disk that it was part of an array

Now remove the array from the mdadm.cong file and rebuild the RAM image in initr. WE may need to find the UUID for the drives, blkid lists them all.

So you already have a RAID 5 array and you want to make it bigger. You can either swap out each disk one at a time for a larger disk or simply add an new disk to the existing array. When I say simply there is a scary bit at the end.

TIP:Install VMware and play around with RAID drives using a virtual guest first. You can create a miniature copy of your own real system and then make a copy of that before testing out these RAID configurations.

Ok, so you have a VMware test system or you have complete backups of your system. Now read all this HOWTO before doing anything.


Assuming your existing RAID 5 array has 3 disks (sdb1, sdc1, sdd1) and is called md0. You will need to install the new drive and then partition it and set the ID to 0xDA - Non-fs data or 0xFD - Linux raid autodetect, ready for use and then add the new disk to the array.

Pages: 1 · 2 · 3 · 4

If you use the CPU scaling options that are now a default part of Ubuntu, you will also see that when folding@home runs or any other process that hits the CPU's hard the CPU frequency will jump up a level or two. Folding@home run as a low priority using nice. To stop any nice process from pushing the CPU to its limits add the following code snippet into the existing file /etc/init.d/ondemand. If will replace the start and background switch commands. I also want to set the minimum for my frequency for CPU too.

Now whenever you boot the file that tells the CPU scaling to ignore nice processes will be set.

Ubuntu documentation on Installing Folding At Home
Team Ubuntu Stats