Least Queue Depth With Subset

The least queue depth with subset policy is also known as the least I/Os or least requests policy. This policy routes the next I/O request to a data path that has the least outstanding I/O requests queued. For this policy, an I/O request is simply a command in the queue. The type of command or the number of blocks that are associated with the command are not considered.

The least queue depth with subset policy treats large block requests and small block requests equally. The data path selected is one of the paths in the path group of the RAID controller module that owns the virtual disk.

Least Path Weight With Subset

The least path weight with subset policy assigns a weight factor to each data path to a virtual disk. An I/O request is routed to the path with the lowest weight value to the RAID controller module that owns the virtual disk. If more than one data path to the virtual disk has the same weight value, the round-robin with subset path selection policy is used to route I/O requests between the paths with the same weight value. The least path weight with subset load balance policy is not supported on Linux operating systems.

Changing Load Balance Policies on the Windows Server 2008 Operating System

Load balancing with the MD3200i series storage array is only available for Windows Server 2008 and later versions of the operating system. You can change the load balance policies from the default round robin with subset by using either the:

•Device manager

•Disk management

To change the load balance policy using Windows Server 2008 device manager:

1From the desktop of the host, right-click My Computer and select Manage to open the Computer Management dialog.

2Click Device Manager to show the list of devices attached to the host.

3Right-click on the multi-path disk device for which you want to set the load balance policies, then select Properties.

4From the MPIO tab, select the load balance policy that you want to set for this disk device.

Appendix—Load Balancing

MD3200i, MD3220i specifications

The Dell MD3220i and MD3200i are part of Dell's extensive line of modular storage solutions, designed to support organizations in optimizing their data management and scalability requirements. These models offer reliable performance and flexible features, making them suitable for various workloads including virtualization, cloud storage, and disaster recovery.

One of the standout features of the MD3220i and MD3200i is their support for iSCSI storage networking. By utilizing the Internet Small Computer Systems Interface (iSCSI) protocol, these systems provide organizations with a cost-effective way to connect their storage over existing network infrastructure, enabling efficient data transfers and management.

Both models are equipped with dual controllers that ensure high availability and failover capabilities, which are crucial for meeting uptime requirements in mission-critical environments. The dual controllers also facilitate load balancing and increase overall system performance, as they allow multiple paths to the storage, enhancing I/O performance.

Scalability is another key characteristic of the MD3220i and MD3200i. These storage arrays can be expanded to meet growing storage demands, supporting up to 240TB of raw capacity with up to 16 additional expansion enclosures. This flexibility allows organizations to start with a smaller configuration and grow their storage capabilities without a complete overhaul of the existing infrastructure.

The units also support multiple disk types, including traditional spinning disks, solid-state drives (SSDs), and a combination of both. This versatility enables users to tailor storage configurations to their specific performance and budgetary needs. Furthermore, the systems feature advanced data management technologies such as snapshots and remote replication, providing essential tools for data protection.

With their ease of management, the MD3220i and MD3200i are designed for straightforward configuration and operation. The intuitive management interfaces allow IT professionals to monitor performance, configure storage, and manage data effectively, ensuring businesses can maintain optimal system availability.

In summary, the Dell MD3220i and MD3200i are robust, scalable, and versatile storage solutions that cater to diverse organizational needs. Their integrated technologies, such as iSCSI support, dual controller architecture, and advanced data management features, make them an ideal choice for modern data centers looking to enhance storage capabilities while ensuring reliability and performance.