OpenBSD Journal

CCD vs RAIDFrame

Contributed by jose on from the fast-disk-hardware dept.

AngryJ5 asks: "what are the differences between ccd and raidframe in OpenBSD? they both seem to do the same thing, given the available options of each, though I suppose raidframe is a bit more robust."

Anyone have an answer and some exprience for AngryJ5?

(Comments are closed)

  1. By Joe Schmoe () on

    Speaking of ccd, is there a ccd tutorial somewhere?

    Also, is ccd something like LVM? Can you resize your partitions on the fly?

    1. By tedu () on

      if you elect not to stripe, you can expand it by adding more disk partitions. if you stripe, you have to use another ccd to concat the first one and the new disk space.

  2. By Teknoenie () on

    CCD offers basic disk contatenation. RAIDFrame on the other hand offers a number of _software_ RAID levels like 0,1,5. remember disk contatenation does _not_ stripe the disks but adds to the end of the physical disk. ie if you have a 5GB disk and a 10GB disk you first must fill up the entire 5GB of the first disk before the concat moves to the second disk. This leaves you open to "hotspots" on a single disk. Striping (0,3,4,5) doesn't have this problem so much.

    1. By tedu () on

      ccd supports striping. read the man page :)

  3. By MotleyFool () on


    since I saw you post on the ccd vs raidframe I thought I'd ask about the status of vinum on OpenBSD? I was wondering if you ever got any feedback on your OpenBSD port of Vinum?

    1. By tedu () on

      it wasn't really complete, some things didn't quite work. at the moment, no plans for integration.

  4. By Anonymous Coward () on

    If you want RAID 0, just use ccd. It provides striping and it is very small. It's part of every kernel, it's well tested and works great. If you need RAID 1 or higher, you need to use RAIDframe. It bloats up the kernel, and it is not documented as well as it should be. But it works.

    1. By pravus () on

      not documented? try 'man raidctl'. it has everything you need to know. i've set up quite a few RAIDFrame sets using just the information in that man-page.

    2. By M:son () on

      RAIDframe works excellently and is very well documented.
      man raid
      man raidctl

      Should take most people even those new to OpenBSD through the process of installing software RAIDframe without too much hassle.
      The prerequisite is that you know what RAID is, how it works and that you have a general idea of the various raidlevels.

      1. By Anonymous Coward () on

        I never said that it was NOT DOCUMENTED. I said that it was NOT DOCUMENTED AS WELL AS IT SHOULD BE.

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