The configuration of a Dell EqualLogic PS5000E storage array with VMware vSphere and a Windows Server VM involves several considerations, particularly regarding iSCSI connectivity and multipathing. Understanding whether the Dell EqualLogic Multipathing Extension Module (MEM) is required when the storage is not directly presented to ESXi is crucial for maximizing performance and reliability.
Configuration Overview
The setup involves a single Dell EqualLogic PS5000E array with firmware version 7.0.5, having a dual-controller configuration. NIC0 and NIC1 on each controller are dedicated to the iSCSI VLAN, while NIC2 is used for the management VLAN. The environment is running VMware vSphere 5.5, using a software iSCSI initiator.
- Each ESXi host is equipped with two physical NICs configured for the iSCSI VLAN.
- The iSCSI network is set up on a standard vSwitch with two vmkernel ports. Each port is configured with one physical NIC as active and the other as unused, ensuring proper port binding for redundancy and load balancing.
- Within this setup, the PS5000E is not directly used as a VMDK datastore for ESXi hosts but is presented directly to a VM running Windows Server 2012 R2. The VM accesses the storage using an iSCSI initiator with NTFS formatting.
Multipathing Considerations
The core question is whether the Dell EqualLogic MEM is necessary for MPIO (Multipath I/O) between a VM and the PS5000E when the storage is not directly accessed by the ESXi hosts.
MEM and VMware ESXi
The Dell EqualLogic MEM is designed to optimize iSCSI communication between EqualLogic arrays and VMware ESXi hosts by providing advanced multipathing capabilities. It enhances load balancing and failover mechanisms beyond VMware’s native multipathing.
However, since the storage is not presented to the ESXi hosts directly and is instead accessed through a VM, the typical benefits of installing MEM on ESXi hosts do not apply. The VM itself is responsible for initiating iSCSI sessions to the PS5000E.
Windows Server MPIO
The Windows Server VM uses Dell EqualLogic Host Integration Tools (HIT) for Microsoft, which manages MPIO at the OS level. These tools recognize EqualLogic storage arrays and configure optimal MPIO settings tailored for Windows environments.
By configuring two virtual NICs for the VM on the iSCSI VLAN, the setup allows for bandwidth aggregation and network redundancy, facilitating efficient and reliable access to the PS5000E without requiring ESXi-level multipathing extensions.
Conclusion
Given the described setup, installing the Dell EqualLogic Multipathing Extension Module on ESXi hosts is not necessary. The setup relies on Windows Server’s MPIO capabilities managed by HIT, ensuring effective iSCSI connectivity and performance for the VM accessing the storage. Proper network configuration with virtual NICs enhances bandwidth utilization, aligning with typical best practices for virtualized environments.
