Device Emulation Types; Failover - HP XP7 Configuration Manual

Device emulation types

The XP7 family of disk arrays 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).
FX Devices (3390-3A/B/C, OPEN-x FXoto): The Data Exchange feature allows you to share
data across mainframe, UNIX, and PC server platforms using special multi-platform volumes.
The VLL feature can be applied to DE devices for maximum flexibility in volume size.
(FX Devices—Not applicable to NonStop, Novell Netware, OpenVMS, and VMware)
NOTE: When the XP7 is 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 might cause data loss in the external storage
LUNs. For new deployments, use OPEN-V, because some features (such as features available with
HP XP7 Snapshot Software or HP XP7 Continuous Access Journal Software) are only supported
with OPEN-V.
For detailed information, see

Failover

Depending on the operating system used, the disk arrays support many standard software products
that provide host, application, or I/O path failover, and management.
HP-UX
Alternate link for I/O path failover (included in HP-UX)
Logical volume management (included in HP-UX)
OpenVMS
The XP7 family of disk arrays is supported with OpenVMS's resident Multipath software, which
provides I/O path failover.
Solaris
The Veritas Cluster Server, Solaris Cluster, and Fujitsu Siemens Computers PRIMECLUSTER
host failover products are supported for the Solaris operating system. See the documentation
for these products and Oracle technical support for installation and configuration information.
Your HP representative might need to set specific disk array system modes for these products.
Check with your HP representative for the current versions supported.
For I/O path failover, different products are available from Oracle, Veritas, and HP. Oracle
supplies software called STMS for Solaris 8/9 and Storage Multipathing for Solaris 10. Veritas
10 Overview
"Emulation specifications (HP-UX)" (page 113).