Disk partitioning changes with anaconda

Wednesday, 18, December 2013 Jim Perrin Installation 8 Comments

With previous el5 and el6 installs, I would clear the disks, and accept the default lvm layout, though I would adjust the sizes a bit. Ordinarily when I adjusted the sizes, I would leave myself additional free space within the volume group so that I could grow later as needed.

Upon installing the rhel7 beta, I discovered this is no longer how disk allocation works. After you select your disk(s) and adjust the sizes of the logical volumes how you wish, anaconda creates partitions just large enough to cover the space you assigned. To the end user, this means that immediately following installation the volume group is 100% full, with no free space immediately visible. To use the rest of the free space on the disk, you must create more partitions, initialize the new partitions as physical volumes, and add them to the volume group. Only then will you be able to use your remaining free space.

8 thoughts on "Disk partitioning changes with anaconda"

  1. daveStyle says:

    I don't quite understand the advantage to this approach.
    If it was tight enough then there wouldn't even be enough space to yum update out of the box - Danger Zone.

    1. Jim Perrin says:

      The file system isn't created full, the pv and underlying volume groups are. There's still room in the file system. It's simply a ~7 step process to grow the file system now instead of a 3 step process.

      1. daveStyle says:

        Yep, I didn't see LVM mentioned in the post so I thought it was the root XFS filesystem. Thanks for the reply.

  2. Johnny Hughes says:

    Well, the advantage of a small system partition and larger data and home partition with a bunch of free space would be that you could do things like ... do a system re-install on the system partition and have your home and data partitions still contain data from the old install. When you get everything working, you are done and you did the upgrade on the existing hardware.

    You can also easily create another LVM partition (or even Physical Volume and Volume Group, then LVM) and do a multiboot machine, etc.

    You can also still easily add space to the other LVMs, if needed.

    So it gives you flexibility to do things other than a standard install.

    In the age of disposable commodity VMs or Servers with failover capability and shared backend storage these things are now much less important (most of the time, home directories and data live off the machine now anyway) .. but especially for testing workstations, it is still good to have this kind of flexibility.

    1. Akemi Yagi says:

      There is a post related to the "free space" issue in this RHEL discussion session:


  3. Martin says:

    You should be able to "Modify…" the volume group [1], it's the "Configure Volume [Group]" dialog as seen in the Btrfs documentation [2]. This works at least with Fedora 20 (I created a LVM VG with free space on LUKS) and the option is already available in Fedora 19. It's not as flexible as it used to be and apparently somehow hidden (it's not the first time I've heard of this problem). There are a few things which could be better but I still prefer it to the old Anaconda.

    [1]: https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/7-Beta/html/Installation_Guide/Create_LVM-x86.html
    [2]: https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/7-Beta/html/Installation_Guide/Create_Btrfs-x86.html

  4. Sylvain says:

    Well, what's this unusable tool ?

    To install CentOs on a simple server with 2 disks, I found no way to partition a simple raid 1, the first partition take all drive space, impossible to define a small swap...

  5. Sylvain says:

    Viva Youtube !
    on this video https://www.youtube.com/watch?v=c-N08aU1h50 I discoverd that even if the help tell "70 Gio", you must enter "70GB" otherwise it uses all free space...

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