About HPE Storage Connection Manager

The HPE Storage Connection Manager is designed to simplify making and maintaining the optimal number of iSCSI connections (also known iSCSI sessions) between the Windows host and the array. The HPE Storage Connection Manager feature is designed for arrays running array OS 2.x and later that are using the Automatic iSCSI Connection Method under Network Configuration Group settings.
NOTE:

Beginning with the release 5.1.1.0, the HPE Storage Connection Manager supports both Volume Scoped Targets (VST) and Group Scoped Targets (GST). The HPE Storage Connection Manager can support VST-only or GST-only configurations, and those that include a mix of VST and GST targets.

IMPORTANT:

If you update to release 5.1.1.0, you must also update the Windows toolkit to version 6.0.0, because older versions of the connection manager cannot display iSCSI GST volumes.

Volume Scoped Target (VST)

  • The array presents its discovery IP as its target portal, and each connection is redirected across the data ports to spread the connections.
  • Each volume appears as a single iSCSI target in the list of iSCSI discovered targets.
  • Each target supports only a single LUN.
  • A maximum of 8 connections per target are supported.
  • The connection manager only makes connections from each initiator to each array in the group.
NOTE: HPE Storage arrays shipped with release 5.1.1.x and later have GST enabled by default.

If you upgrade to array OS release 5.1.1.x instead of doing a new installation, your default target will continue to use VST.

Group Scoped Target (GST)

  • The group reports a single iSCSI target.
  • Multiple volumes are reported as individual LUNs under a single GST.
  • A maximum of 32 connections per target are supported.
  • The target presents the data ports directly, and the array itself does not perform any redirection.
  • HPE Storage Connection Manager creates full mesh connections, which means that a connection is made from each initiator port to each target portal.
NOTE: SMI-S does not support GST.

Setting up iSCSI connections to achieve optimal performance and redundancy requires knowledge and attention to detail. The HPE Storage Connection Manager feature brings all the things you need to make initial iSCSI connections in one place, and helps you verify that the connections are correct. The HPE Storage Connection Manager GUI makes the optimal number of connections to a target at the request of the user instead of forcing the user to make each connection one at a time.

The optimal number of iSCSI connections to a volume to achieve redundancy and performance depends on the:
  • Number of host network interfaces
  • Array network interfaces and their subnets
  • Number of arrays involved in the volume
When you ask HPE Storage Connection Manager to connect to a Storage volume, with one request HPE Storage Connection Manager:
  • Gathers interface, subnet, and volume information
  • Calculates the optimal number of connections
  • Determines which host network interfaces are in the same subnets as the array network interfaces
  • Attempts to make the optimal number of connections
When the connections are established, the HPE Storage Connection Manager GUI displays connections and the information necessary to easily verify that the connections are optimal, are reestablished on reboot, and do not cross subnets.
The HPE Storage Connection Manager feature has two major components, which are described in the following table.
Table 1. Components of the Connection Manager Feature
Component Function
HPE Storage Connection Manager GUI Calculates and establishes the initial optimal number of connections to each Storage volume at the request of the user.
Connection Service Calculates and maintains the optimal number of connections to each Storage volume. Connection service monitors changes to the host and to the array over time, and adjusts the optimal number of connections as needed.

Host changes over time include changing the network interfaces. Array changes over time include adding an array, merging a pool, evacuating an array, and changing between manual and automatic iSCSI connection modes.

Connection service also compensates for manually added connections by automatically removing them, and for manually deleted connections by restoring them.

The HPE Storage Connection Manager GUI and connection service calculate the optimal number of iSCSI connections based on the number of host initiator ports and array target portals.

By default, the HPE Storage Connection Manager feature establishes no fewer than two connections and no more than eight (for VST), or thirty-two (for GST) connections. If you need to change these default values, contact support for assistance.

The Device Specific Module supports only the following load-balancing policies:
  • Round Robin
  • Least Queue Depth
  • Least Blocks
HPE recommends Least Queue Depth as the optimal load-balancing policy. Selecting any load-balancing policy other than these three, defaults to Least Queue Depth.
NOTE: NCS ignores release 1.x and release 2.x array volumes on arrays using the manual iSCSI connection method. However, the HPE Storage Connection Manager GUI can establish connections to both.

HPE Storage Connection Manager Feature iSCSI vs. Windows iSCSI

Why use the HPE Storage Connection Manager feature when Windows comes with its own iSCSI Initiator application?

Table 2. HPE Storage Connection Manager vs iSCSI Initiator
HPE Storage Connection Manager Feature Windows iSCSI Initiator Application
Simple – Designed to work with HPE Storage arrays. Has all the features you need without added complication. Complex – Has to work with any and all iSCSI targets. Most features are not used with HPE Storage arrays.
Calculates the optimal number of connections automatically. You must calculate how many connections you need.
Establishes the optimal number of connections automatically. You must establish your connections manually.
Can establish multiple iSCSI connections at the same time. Can establish just one iSCSI connection at a time.
Monitors changes to the host and to the group hosting the volume over time. Does not monitor changes to the host and group.
Adjusts the optimal number of connections as needed. You must add or remove connections manually.
Removes superfluous connections automatically. Does not recognize a superfluous connection. You remove the connection manually.
Restores manually deleted connections automatically. Does not recognize a deleted connection. You restore the connection manually.
The DSM driver is designed to work with HPE Storage arrays. MPIO designed to work with any and all iSCSI targets. Usually works with most.

When you choose the HPE Storage Connection Manager feature to setup and manage your iSCSI connections (sessions), you no longer need to use the Microsoft iSCSI Initiator applet.