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11 Comments

  1. 5

    Adam Williamson

    Thanks for writing this article, it’s nicely done and almost entirely correct. However, it’s not true to say that “Apparently, it will not because the Live CD editions of Fedora 16 do not support creating anything other than the default LVM partitioning scheme.” The live installer is restricted, but not that restricted. The restriction is that the root partition (in fact, any partitions which contain files from the actual system image, so if you were to split out /usr or /var, for e.g., the restriction would apply to those too) must be ext4. You can create a partition layout manually, have the sizes be whatever you want, use LVM or not, use encryption or not – but the partitions with system files on must be ext4. The reason is simple: Fedora live images are actually compressed snapshots of an ext4 filesystem, and the live installation process does not take actual .rpm package files from a disc or repository and install them one by one, as the ‘traditional’ installer does, it just essentially writes the filesystem image directly onto the disk. To do this, the target filesystem(s) have to be the same as the source, i.e., ext4. You can’t write an ext4 filesystem image to a btrfs partition.

    Reply
  2. 4

    JFM

    Who cares? If it is a server you reboot it once ayera or less. If ir is a desktop you suspend it and only power it off when you are leaving for a week or so. And anyway even if using systemd activating LVM is only a small part of boot time.

    About people saying LVM is slower, it is like peole saying you should compare your own kernel: none of them has bothered running a benchmark. Now, logically LVM should be slower or at least use more CPU time. It doesn’t. Now if you think at it the overhead for finding the right block is something in the order of a couple dozens of CPU cycles. Also my LV was in pristine condition: if it is fragmented due to having ben extended multiple times then it _will_ be slower than a partition because there will be head movements but of course the point is moot because the partition would have become full and if you were able to carve a new one then you could have done the same thing with LVM.

    Also there is a nice thing with LVM: you can give them significanty names so you don’t need neither mounting them nor running a special tool (for reading labels) to know what you have stored in them.

    Reply
    1. 4.1

      Hedayat Vatankhah

      I personally have used LVM since it became the default in Fedora. And yes, its flexibility helped me considerably (and this is why I kept using it).
      Anyway, searched a little and it seems that you are right that LVM doesn’t degrade performance much by itself.

      Reply
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  4. 3

    TGM

    I’m going to agree with your Anaconda… statement with one small hiccup – Time Zone selection is very finicky due to the small size of the world map.

    Reply
    1. 3.1

      finid

      True. I wish they will use the same system employed by Ubuntu.

      Reply
  5. 2

    Hedayat Vatankhah

    Non-LVM partitioning has an advantage over LVM method: speed…

    Reply
    1. 2.1

      JFM

      I benchmarked LVM vs non-LVM on the same physical partition and there was no difference.

      Reply
      1. 2.1.1

        Hedayat Vatankhah

        I have not compared it myself but I have read it in many places. Even in the case you mentioned, it is *possible* to achieve higher boot speeds if you don’t use LVM (you’ll need to disable some services running at boot by systemd).

        Reply
        1. 2.1.1.1

          finid

          Are these “higher” (faster) boot speeds really that much? At best, are we not talking no more than 2 or 3 seconds here? The benefits of LVM far outweigh that reduced boot time.

          Reply
          1. 2.1.1.1.1

            Hedayat Vatankhah

            Well, apparently it could be around 8 seconds for a machine: http://lists.fedoraproject.org/pipermail/devel/2011-October/157732.html

            But yes, LVM benefits might outweigh the gains.

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