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November 06, 2009

Disks and their alignment

The idea of disk alignment has come up around our environment. We are not seeing any dramatic effects of of this currently, however since we are still young in the game ov VMs in general we might as well get started off right.

To that end I have started to work on realigning the templates for linux hosts. I have worked up a quick idea of how to make this work, we'll see how it goes.

Hope it works!

All this is to avoid another dredded install :-) And of course its fun to monkey with disks like this.

Posted by Kevin Foote in work on November 06, 2009

October 27, 2009

Disk resize redone

I have a few templates that I use when deploying Linux based VMs around here. These come pretty stripped down and minimalist. Getting them up to a usable system is fairly quick with vmware.

But I just made it a bit quicker with my latest template.

The use of LVM is pretty slick for disk type stuff and I was amazed how simple it was to resize and work with the system and other disks. I have just stream-lined my disk growing process by locating the swap space on a LV rather than out on a separate disk partition. This makes the growing of a system disk especially quick and simple.

  • Do the initial low level work with fdisk /dev/sda. This will be resizing only /dev/sda2 to the max cylinders. Reboot to sync new partitions.
  • Now we just have to run pvresize and lvresize.
    > pvscan
      PV /dev/sda2 VG VolGroup00 lvm2 [14.88 GB / 0 free]
      Total: 1 [14.88 GB] / in use: 1 [14.88 GB] / in no VG: 0 [0 ]
    > pvresize /dev/sda2
      Physical volume "/dev/sda2" changed
      1 physical volume(s) resized / 0 physical volume(s) not resized
    > lvscan
      ACTIVE '/dev/VolGroup00/LogVol00' [10.97 GB] inherit
      ACTIVE '/dev/VolGroup00/LogVol01' [3.91 GB] inherit
    > lvresize -l +100%FREE /dev/VolGroup00/LogVol00
      Extending logical volume LogVol00 to 27.97 GB
      Logical volume LogVol00 successfully resized
    > lvscan
      ACTIVE '/dev/VolGroup00/LogVol00' [27.97 GB] inherit
      ACTIVE '/dev/VolGroup00/LogVol01' [3.91 GB] inherit

By placing the swap on the same PV as the / we don't have to muck with moving the swap around any longer. And by using the -l +100%FREE option on the lvresize command it lets lvresize do the work of giving us the whole chunk of new disk.

Well it speed thing up a little anyway..

Posted by Kevin Foote in work on October 27, 2009