HP StorageWorks SAN Virtualization Services Platform Best Practices Guide (5697-0935, May 2011)

8 Hosts
Before adding or configuring a host, you must check the latest release notes or SPOCK for support.
When configuring hosts, consider the following:
• All hosts must have at least two HBA ports. Each HBA should be in a zone with both DPMs.
This is called a fully cross-connected front-side.
• Hosts must not be zoned to see the VSMs over the Fibre Channel SAN.
• After presenting or removing any new virtual disks to a host, perform a rescan on the host to
discover the new (or absent) virtual disks.
• For Windows 2003 servers use diskpart to align the operating system to boundaries friendly
to array. For more information, see "Aligning the system partitions for Windows (pre-2008)"
in the HP StorageWorks SAN Virtualization Services Platform Administrator Guide.
• If a Windows host detects a new device, you are prompted to format it. If this is unexpected,
it may indicate a zoning problem. Do not allow Windows to format a device without careful
consideration.
• UNIX and Linux hosts may need to be awakened (ioscan) to scan for the first LU that is
presented to them.
• SVSP does not have cache for I/O, and therefore scales very well, but is sensitive to high
spikes in I/O load (for example, no buffering). HBA I/O throttling is a proven mechanism for
leveling out the spikes in I/O traffic. Typically, HBA vendors provide a tool to accomplish this.
• Only zone a host to the DPM pairs that are presenting LUNs for that host. While all DPMs
must see all of the storage on the back-end, the front-end has no such restriction, and
unnecessary resources will be consumed.
Operating system and application considerations
VMware ESX
Review Table 1 (page 34) before configuring an ESX host.
Table 1 Shared storage requirements
Clusters of physical and
virtual machines (standby
host clustering)
Clusters across physical
machines (cluster across
boxes)
Clusters on one physical
machine (cluster in a box)Storage type
NoNoYes (recommended)Virtual disks
YesYes (recommended)NoPass-through RDM (physical
compatibility mode)
NoYesYesNon-pass-through RDM
(virtual compatibility mode)
NOTE: Clusters across physical machines with non-pass-through RDM is supported only for clustering with Windows
2000 Server or Windows Server 2003. It is not supported for clustering with Windows Server 2008.
34 Hosts