[linux-lvm] Viewing logical/physical mapping when striping

Dax Kelson dax at gurulabs.com
Wed Jun 30 22:34:41 UTC 2004

On Wed, 30 Jun 2004, David J N Begley wrote:

> Here's where my mind really gets screwed-up - if I throw data at the LVs, the
> read/write pattern tends to indicate that the striping _is_ working, which
> then contradicts the mapping that 'lvdisplay -v' shows!
> What's happening?  Are LEs always mapped to PEs in a linear fashion whilst
> striping occurs at some lower (per-chunk-of-an-LE) layer?

My understanding that this behaviour you are seeing is coming from the 
*filesystem* (ext3, or whatever you are using).

I bet if you used dd, such as:

dd if=/dev/zero of=/dev/VG0/LV0 

And watch the write pattern it would be linear.

Dax Kelson
Guru Labs

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