Tuesday, November 24, 2009

LVM

Just a short note. Since I often try new distributions, I finally came up with a way to not lose my data. I use the LVM (Logical volume management) which never gets formatted (unless I do something really dum). The problem with restoring files to /home/rose is that the settings files (the ones after a dot) are also there. Now, when I reinstall, I create soft links (ln -s) to files in the LVM which are always there. These are Documents, Pictures, etc.

The concept of the LVM is a little strange, but there are some simple commands that always tell you what the setup is. I have notes written in long hand.

This entry is very choppy but I am trying to record what I have done here.

3 comments:

  1. Well, the purpose of this LVM entry was to record information that I need, should I have to re-install the Linux OS. Here I am, I had to re-install linux and forgot how to mount the LVs. I cannot find my notebook.

    Commands:
    $sudo lvdisplay gives me a list of my LVs. I see that the status is NOT available.

    $sudo pvdisplay shows the physical volume, /dev/sda8. (I actually forgot that this partition contained my LVs and had recently tried to reformat it from Windows XP. Luckily, the format command was refused.

    After some searching, I found the command that must be run first. It will activate all LVs that it can find. (Reference, 2006). Note that the name of my volume group is system. This is not a very good name, I must admit. It should be more personalized to make clear that I created it and it is not part of the Linux setup.

    $sudo vgchange -a y gives this result >>> 4 logical volume(s) in volume group "system" now active.

    Now that the LVs are activated, open the Logical Volume Management application and follow the menu items:

    Volume Groups-> system -> system logical view -> list of LVs

    Click on one of the LVs and the image will change. Click on the properties button and a window will pop up.The filesystem is automatically chosen as ext3 and I am permitted to create a directory of my choice. The created directory will have _lvm appended to the column name. i.e. nobackup LV will be mounted on nobackup_lvm.

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  2. On another Linux system, had to install lvm2 from Synaptic Package Manager, but it did not install the graphic interface. Did that from Ubuntu Software Center.

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  3. Just mounted my LVMs, which I created on Ubuntu, on my new OpenSUSE partition. LVMs are a handy way to do work using different linux OS's

    "2 logical volume(s) in volume group "lvm_rose" now active"

    But where are they? I copied the fstab info from Ubuntu. After running sudo mount -a (to mount everything in fstab) I get an error that there is no mount point. After searching a while, I realize that I forgot to create a directory to which the lvm will be attached. Now I will reboot and see if everything works as planned.

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