DFM 4.0 Aligned WAFL Ops

[erick_moore]

We recently installed DFM 4.0, and on a few LUN's we are seeing basically 99% unaligned OPS.  As an example we have an Exchange LUN, LUN type of Windows from the NetApp side, and from the Exchange server the LUN was aligned to the 32K partition offset.  So if my LUN is configured properly from the NetApp side, and from my host it is aligned, why am I seeing all these unaligned WAFL ops?

[BrendonHiggins]

Have you checked the host to see what is going on?

http://support.microsoft.com/kb/929491

If you are running VMs ~ http://theether.net/kb/100104

Hope it helps

Bren

[erick_moore]

Yes, the disk are aligned in Windows.  We use a 32K offset for our NetApp attached Windows LUN's.  VMDK's OS partitions are also alligned.  That is why I don't understand why I am seeing this output.  Everything is alligned yet we are not getting any WAFL aligned ops.

[tfuchs · Accepted solution]

Is this a physical server or a virtual server with RDMs ?

In both cases you only need to choose the correct LUN type (in your case "windows") on the storage controllers and you MUST NOT align the LUN from the Windows host side.

The LUN type within ONTAP takes care about the Windows partition offset and aligns the LUN correctly. If you do a partition alignment to 32K on the Windows host you change it back to a mis-aligned LUN.

If you have a LUN which is presented to an ESX host you have to choose "vmware" as LUN Type because ESX will write its VMFS on the datastore. In this case, all windows 2000/2003 vmdk's have to be aligned to 32K or another value which must be divisible by 4096.

Hope this helps

Thorsten

[erick_moore]

Hot damn!  Thanks so much tfuchs, I never realized that.  Now I have a bunch of RDM's to robocopy....