Migrate 2003 server cluster to 2008 R2 server cluster - LUN misalignment

[vacouser]

We are migrating from 2003 two node cluster to 2008 two node cluster. The 03 servers have multiple Netapp cdot shared luns which contain files. The luns are setup as 2003 MBR ostype on the netapp side. The migration method will involve moving the cluster resources/services to the new 08 servers. The same LUNs will be used as to avoid copying any data. On cutover the 03 mbr luns will be attached to the 08 servers. The questions are

Since the ostype can't be changed to windows_2008 will there be misalignment and where? If yes is there any way to correct it?

[aborzenkov]

There will be no new misalignment that you did not have already.

[vacouser]

Can you elaborate a bit or point me to a document to understand?

Thanks for the quick response.

[aborzenkov]

OS type affects how LUN is created; "windows" assumes first partition starts at 63 sector so LUN layout is optimized for this. If you already created partition that matched this expectation, this won't change after you connect LUN to Windows 2008. If you created partition that did not match this expectation, you already had misalignment and this won't change after you connect LUN to Windows 2008.

Now if you completely wipe out LUN and create partition from the scratch under Windows 2008, then yes, you are likely to get misaligned partition because Windows 2008 by default starts partition at different offset.