HP StorageWorks Clustered File System 3.6.0 Windows Storage Server Edition Administration Guide (403103-005, January 2008)

Chapter 7: Configure the SAN 65
I/O operations. The exact alignment characteristics vary by manufacturer
and model; consult your storage vendor for alignment recommendations.
This issue occurs because the Windows partition table causes space to be
reserved at the start of the LUN, which can cause a misalignment with the
array’s storage. If your storage array is affected by this issue, the simplest
way to avoid the situation is to create an unused partition at the start of
the LUN and then ensure that the second partition starts on an aligned
boundary. The Windows Logical Disk Manager or utilities such as
diskpart can be used to create the partitions.
Import SAN Disks
SAN disks to be used for PSFS filesystems must be imported into the
cluster. This step gives the cluster control over access to the disks. Before
importing disks, you should be aware of the following:
• If servers from multiple clusters can access the SAN via a shared FC
fabric, avoid importing the same disk into more than one cluster.
Filesystem corruption can occur when different clusters attempt to
share the same filesystem.
• Only basic disks can be imported. Dynamic disks are not supported.
• Shared disks must be partitioned before they are imported into the
cluster. If there is not a partition table in place on the disk, you will not
be able to access it via HP Clustered File System.
If you want to extend a PSFS filesystem and the underlying partition,
you can use the Extend option provided on the HP CFS Management
Console. To make other changes to the partition table after a disk has
been imported, you will need to deport the disk, make the changes
with the Windows Disk Management utility, and then import the disk
again.
• HP Clustered File System supports a maximum of 31 partitions on a
disk. Disks containing a larger number of partitions cannot be
imported into the cluster. (If you upgraded from an HP Clustered File
System release earlier than 3.4, you may currently have imported
disks or LUNs with more than 31 partitions, and may have created
dynamic volumes using those higher-numbered partitions. See “Disks