[CentOS] Installing on partitionable RAID arrays

Raja Subramanian rajasuperman at gmail.com
Thu Mar 26 14:29:37 UTC 2009

On Thu, Mar 26, 2009 at 5:42 PM, RedShift <redshift at pandora.be> wrote:
> Since linux 2.6, the md layer has a feature called partitionable arrays. So instead of having two disks, creating an identical partition table on both and then putting those partitions in RAID 1, you take those two disks and put them in one partitionable RAID 1 array (in mdadm terms, "mdp") and create a partition table on the new RAID device. The advantages are quite clear compared to the old non-partitionable arrays.

For the uninitiated, would you be kind enough to elaborate the
advantages of mdp?

I have always created identical partitions on the raw disks first,
and the used mdadm on top.  I also create my partitions ~200MB
smaller than raw disk capacity to ensure minor size differences
between disks (eg. 160GB HDD from Seagate is not exactly same
size as a 160GB disk from Samsung) will not prevent me from
adding them to a raid set.

Does mdp handle this scenario?

- Raja

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