[linux-lvm] pvcreate and partition alignment

[Bryn M. Reeves]

On Thu, 2009-03-12 at 09:52 -0500, Eugene Vilensky wrote:
> Greetings,
> 
> NetApp requires for best performance that all partitions be aligned to
> 4k boundaries to prevent "partial writes" and lost IOPS.  We are using
> LVM on un-partitioned devices.  The only response I can get out of
> NetApp is that, by not having a partition, the partition itself is not
> mis-aligned.  

You need to make sure that the extents on the PV have the correct
alignment.

> We are using a blocksize of 4096b for ext3.  
> 
> Is there another "allocation" setting that we need to select for LVM
> specifically, to ensure alignment to this 4k NetApp boundary?

See this thread on lvm-devel last month:

https://www.redhat.com/archives/lvm-devel/2009-January/msg00148.html

Regards,
Bryn.