Device Emulation Types; Failover - HP StorageWorks XP10000 - Disk Array Configuration Manual

Short-wave non-OFC (open fiber control) optical interface
Multimode optical cables with SC or LC connectors
Public or private arbitrated loop (FC-AL) or direct fabric attach
Fibre Channel switches
Even though the interface is Fibre Channel, this guide uses the term "SCSI disk" because disk array
devices are defined to the host as SCSI disks.

Device emulation types

The XP family of disk arrays and the SVS 200 support these device emulation types:
OPEN-x devices: OPEN-x logical units represent disk devices. Except for OPEN-V, these devices
are based on fixed sizes. OPEN-V is a user-defined size based on a CVS device. Supported
emulations include OPEN-3, OPEN-8, OPEN-9, OPEN-E, OPEN-L, and OPEN-V devices.
LUSE devices (OPEN-x*n): Logical Unit Size Expansion (LUSE) devices combine 2 to 36 OPEN-x
devices to create expanded LDEVs larger than standard OPEN-x disk devices. For example, an
OPEN-x LUSE volume created from ten OPEN-x volumes is designated as OPEN-x*10.
CVS devices (OPEN-x CVS): Volume Size Configuration (VSC) defines custom volumes (CVS) that
are smaller than normal fixed-sized logical disk devices (volumes). (OPEN-V is a CVS-based custom
disk size that you determine. OPEN-L does not support CVS.) Although OPEN-V is a CVS-based
device, the product name in the SCSI inquiry string is OPEN-V opposed to the fixed size OPEN-
[389E] devices that appear as OPEN-x-CVS.
LUSE (expanded) CVS devices (OPEN-x*n CVS): LUSE CVS combines CVS devices to create an
expanded device. This is done by first creating CVS custom-sized devices and then using LUSE to
combine from 2 to 36 CVS devices. For example, if three OPEN-9 CVS volumes are combined to
create an expanded device, this device is designated as OPEN-9*3-CVS. OPEN-V devices are
designated as OPEN-V*n (without CVS).
NOTE:
For the SVS 200, and the XP24000/XP20000/XP12000/XP10000 when connected to external
storage devices, HP recommends using OPEN-V as the emulation the array makes visible to the host.
This allows configuration of external storage LDEVs without losing data. Using any other emulation
may cause data loss in the external storage LUNs. For new deployments, OPEN-V should be chosen
because some features (such as HP StorageWorks XP Snapshot Software or HP StorageWorks XP
Continuous Access Journal Software) are only supported with OPEN-V.
For detailed information, see

Failover

The disk arrays support many standard software products that provide host, application, or I/O path
failover and management.
The following are supported for HP-UX:
HP Multi-Computer/ServiceGuard (MC/ServiceGuard) software for application failover
Alternate link for I/O path failover (included in HP-UX)
Logical volume management (included in HP-UX)
8 Installing and configuring HP-UX for the XP disk array
"Emulation specifications" on page 37.