DMP overview


DMP overview
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Dynamic Multi-Pathing (DMP) adds fault tolerance to disk storage by making use of multiple paths between a server or a host and a disk in a storage array. In previous releases, DMP was only available as a feature of Storage Foundation.

The paths on an array are set up to work in two ways - either in Active/Active mode, which provides load balancing of the data between multiple paths, or in Active/Passive mode, in which only one path is active and any remaining paths are backups.

The Dynamic Multi-Pathing functionality is offered as DMP device-specific modules (DSMs).

Note:

Windows Management Instrumentation (WMI) is a required service for the MPIO feature to work. Without this service, the MPIO Provider does not load and MPIO objects are not displayed on the VEA console or CLI command outputs. MPIO operations too cannot be performed in absence of WMI service.

DMP DSMs are designed to support a multi-path disk storage environment set up with the Microsoft Multipath I/O (Microsoft MPIO) solution. DMP DSMs work effectively with Windows to provide a fault tolerant multi-path disk storage environment. DMP DSMs have the following benefits:

Fiber Channel StorPort Miniport HBA Driver support
iSCSI HBA support
Microsoft iSCSI Software Initiator support
Boot from SAN support
Active/Active Dynamic Multi-Pathing with clustering support
DMP DSMs load balancing support
Load balancing support includes the following:
- Round robin load balancing support (Active/Active)
- Fail Over Only (Active/Passive)
- Dynamic Least Queue Depth load balancing support
- Round robin with Subset load balancing support
- Least Blocks load balancing support
- Weighted Paths load balancing support
- Balanced Path load balancing support

For DMP DSMs, Boot and data volumes are supported on the same bus/HBAs for non-clustered servers if the Boot from SAN recommendations from Microsoft is followed. DMP DSMs are not supported with Fibre Channel port drivers, Fibre Channel SCSI Miniport drivers or boot or cluster disks on the same bus/HBAs.