I suppose that growing a RAID 1 array is not very common but I had a client that wanted to go from a 2 disk array to a 3 disk array so that one disk could be rotated out periodically and kept off-site. Here were the steps:

• mdadm --add /dev/mdX /dev/sdXX
  • This adds the partition to the array as a hot spare.
• mdadm --grow /dev/mdX -n 3
  • This increases the number of disks from 2 to 3.

I’ve been reading through the launchpad bugs for Xen and thought that I could use them to illustrate some tips and tricks for using Xen in Ubuntu or Debian. I ran into some problems with Xen today on a system after having been upgraded from Ubuntu 7.10 to Ubuntu 8.04 and from Xen 3.1 to Xen 3.2. This should help as a checklist when diagnosing various Xen problems.

Although this version of rubygems should show up in hardy-backports I’m not sure it will ever be ported to gutsy-backports. So I decided to pull the new version and install it on my Ubuntu 7.10 (Gutsy Gibbon) systems. I had previously been using 1.0.1 from Debian testing. The steps to install were quite simple. This should work for at least ubuntu 7.10 and 8.04 and perhaps other versions as well.

A new kernel, 2.6.24-17, has been released for Ubuntu 8.04 (Hardy Heron) in the hardy-updates repository. This kernel may fix at least 1 xen bug (bug 218126, bug 204010) which I’m anxious to test. I’ve held off upgrading any Xen user domains until these were resolved. I think it would be a good time to at least test an upgrade, and since virtualization makes it easy to rollback I think a test is in order. I also noticed that Ubuntu 7.10 got some new kernel modules in the gutsy-updates repository. Not sure what the changes are but it’s something to be aware of.