RAID Controller Failover Modes

Failover provides redundant access to the virtual disks owned by either RAID controller module on the storage array. Failover happens automatically (and transparently). As a result, the host(s) never loses access through the preferred controller which owns the virtual disk.

Two failover modes are supported:

Host-based Multi-Path I/O (MPIO) for Windows or MPP for Linux

Controller-based Auto Virtual Disk Transfer (AVT)

Host-based uses a multi-path driver installed on the host server to access the storage array. If required, the multi-path driver will issue an explicit command to transfer ownership from the RAID controller module that owns the virtual disk to its peer RAID controller module.

AVT is used only in single-port cluster solutions (see Figure 2-3). I/O access to the Logical Unit Number (LUN) of a virtual disk causes failover. In AVT mode, firmware transfers ownership of a virtual disk to the online RAID controller module. The alternate or backup node in a cluster takes over and issues I/O to the peer controller and moves the virtual disk to itself.

NOTE: Clustering requires simultaneous access from cluster nodes to shared storage. If you have clustering software installed on the host, automatic failback should be disabled to prevent "ping-pong" with single-path failure. For more information on clustering, a link to clustering documentation is included on the MD3000 Resource CD under Product Documentation.

NOTE: If setting up a cluster host, the MD3000 Stand Alone to Cluster.reg file entry must be merged into the registry of each node. If re-configuring a cluster node to a standalone host, the MD3000 Cluster to Stand Alone.reg file must be merged into the host registry. These registry files, which set up the host for correct failback operation, are in the windows\utility directory of the MD3000 Resource CD.

RAID Enclosure Thermal Shutdown

Enclosure management provides a feature which automatically shuts down the enclosure when the temperature within the RAID enclosure reaches dangerous extremes. Thermal shutdown protects the data on the physical disks from corruption in the event of a cooling system failure.

The temperature at which shutdown occurs is determined by the enclosure temperature probe's Nominal Failure Threshold and the Maximum Failure Threshold. These thresholds are default settings that cannot be changed. If the temperature sensors on the backplane or RAID controller module detect a temperature exceeding the Nominal Failure Threshold, a critical event is set; if the Maximum Failure Threshold is hit, shutdown of the enclosure power supplies will occur within 5 seconds.

NOTE: If an MD1000 expansion enclosure reaches critical internal temperatures, the enclosure will be shut down automatically via a thermal shutdown command issued by the EMM firmware.

Using Your RAID Enclosure

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Dell MD3000 owner manual RAID Enclosure Thermal Shutdown, RAID Controller Failover Modes

MD3000 specifications

The Dell MD3000 is a renowned storage area network (SAN) solution recognized for its flexibility, scalability, and high performance. Designed to meet the demands of small to medium-sized businesses (SMBs) and enterprise environments, the MD3000 offers a plethora of features that enhance data management and storage capabilities.

One of the standout features of the MD3000 is its modular design. This allows users to start with a basic configuration and expand their storage capacity as their needs grow. The system can support up to 30 drives, including both SATA and SAS drives, giving users the ability to optimize cost and performance based on their specific requirements. With support for a diverse range of drive types, the MD3000 ensures that businesses can implement a storage solution that aligns perfectly with their performance and budgetary needs.

The MD3000 leverages advanced technologies to deliver exceptional performance and reliability. It is equipped with Intelligent Disk Pools that optimize the allocation of data across drives, ensuring improved access speeds and overall system efficiency. This dynamic management of data not only enhances performance but also extends the lifespan of the storage devices.

Data protection is another critical component of the MD3000. The system features various RAID configurations, allowing users to choose the level of redundancy that suits their operational requirements. Additionally, robust snapshot capabilities help businesses create point-in-time copies of their data, enabling quick recovery in case of data loss or corruption.

Connectivity options are abundant with the MD3000. It supports both iSCSI and Fibre Channel, providing users the flexibility to integrate it seamlessly into existing network infrastructures. This adaptability makes it an attractive option for organizations looking to modernize their storage systems without overhauling their entire architecture.

Furthermore, the MD3000 is equipped with a user-friendly management interface. The GUI enables quick provisioning and monitoring of storage resources while providing insightful analytics and alerts, allowing IT teams to maintain optimal performance with ease.

In summary, the Dell MD3000 is a highly versatile and efficient storage solution that meets diverse organizational needs. Its scalable architecture, advanced features, and strong support for data protection and management make it an ideal choice for businesses aiming to enhance their storage capabilities while ensuring reliability and performance. Whether for virtualization, database management, or general storage needs, the MD3000 stands out as an excellent investment in enterprise storage technology.