kb8190 describes using partitions and proper alignment for best performance. We are using LVM exclusively without partitioning the device before hand. Does running pvcreate on a whole device (in this case an mpath lun) fullfill this note:
"Note that this problem will not occur if partitions are not used on the LUNs (for example, if a filesystem is created directly on the LUN without partitioning).
An authoritative answer on this would be VERY helpful. I'm in good shape when working with customers on both Windows and Netware (NSS is aligned by default which is quite nice) but I haven't been able to nail down the Linux side (which encompasses ext3, reiserfs, LVM, swap, etc.).
You can find a great collection of cook-book stuff for LVM is here. Red Hat has excellent documentation on their site.
The takeaway to this thread for me has been the alignment issue; NetApp couldn't answer if the lack of a partition on a physical volume using Red Hat 4.6, meant that the device was aligned for WAFLs 4k boundary. Red Hat's unofficial answer is that it was using the default properties found in their volume management stack.