HP Storage Provisioning Manager (SPM) Version 2.0 User Guide

Exposing volume presentations in 3PAR Storage Systems
3PAR Storage Systems present a volume in three ways:
• Port Present (PP)—exposes a volume to any initiator through one host port on the array.
• Host Sees (HS)—exposes a volume to one initiator through any array port.
• Matched Set (MS)—exposes a volume to one initiator through one array port.
When SPM presents (imports) a volume that is already presented to one or more initiators, the
SPM behaves as follows:
• SPM ignores any PP presentations (mappings) for the volume.
• An HS mapping (or 'VLUN' using 3PAR terminology) is represented as an SPM presentation
that includes one initiator port and all array ports present in the catalog. Multiple HS mappings
(VLUNs) may be consolidated into a single presentation. For example, HS is used for multiple
initiators with the same host mode to access a volume at the same LUN number.
• MS mappings (VLUNs) are represented as an SPM presentation that include one initiator port
and one array port. Multiple MS mappings (VLUNs) are likely to be consolidated in one
presentation. This would be the case if MS was used to present one initiator to a volume
through more than one array port.
Working with 3PAR Storage System host modes
As explained in Exposing volume presentations in 3PAR Storage Systems, there is not a one-to-one
relationship between SPM host modes and 3PAR host modes (host persona). However, during
automation SPM can map any SPM host mode to a 3PAR host persona. For example, “Windows”
maps to “Generic”. When an SPM creates a presentation, it keeps track of the value it sets; as a
result the next time SPM retrieves volume information from the array, it will be able to map a
“Generic” host persona to the intended SPM host mode.
Presenting volumes on 3PAR Storage Systems
As explained in Exposing volume presentations in 3PAR Storage Systems, 3PAR Storage Systems
offer three ways of exporting volumes: PP, HS, and MS. During service activation, the SPM presents
a volume to an initiator based on the FC Host requirement(s) defined in the service request. The
SPM performs the task as follows:
• SPM deletes any PP presentations for the volume.
• For initiators specified in FC Host requirements of the service being activated, when those
initiators are not already mapped to the volume, SPM always uses HS presentations.
• For initiators that are already mapped to the volume using MS, SPM deletes all MS presentations
and creates new HS presentation(s) that reflects the FC Host requirements of the service request.
• For initiators that are already mapped to the volume using HS, SPM keeps the existing HS
presentation if LUN numbers match or if a LUN number is not specified in the FC host
requirement. Otherwise, SPM deletes the existing HS presentation and replaces it with a new
one using the LUN number specified in the FC Host requirement.
NOTE: This behavior differs from SPM 1.3, which was using MS presentations. By using HS
presentations, SPM 2.0 always maps all ports of the array when presenting a volume (akin to the
approach used for EVA Storage Arrays). However, SPM will not attempt to present the volume if
it does not detect that at least one array port is connected to the same SAN as the initiator’s.
Creating hosts on a 3PAR Storage System
When SPM attempts to present a volume to an initiator, it first probes the array to detect whether
this initiator is known to the array. If it is not, a new host is created for that initiator. The name
given to that host will generally use the host name given in the requirements. If no host name is
specified, the host name will be “SPM_” followed by the WWN of the initiator.
The 3PAR array may have hosts with multiple initiator ports. SPM may create hosts with multiple
initiator ports (e.g. if the requirement specifies this). If an initiator port is already referenced on the
66 Working with 3PAR storage systems