Starting from Storage Foundation 6.0.1, one of feature that was introduced is Dynamic Reconfiguration tool.
From my point of view, this feature is extremely useful because avoiding any kind of service interruption.
Dynamic Multi-Pathing provides a Dynamic Reconfiguration tool. The Dynamic Reconfiguration tool is an interactive tool to automate dynamic reconfiguration of LUNs or HBAs. Dynamic reconfiguration includes addition, removal or replacement of LUNs, and replacement of certain HBAs, without requiring a reboot. The Dynamic Reconfiguration tool simplifies the process, so that you do not need a complex set of DMP and operating system related commands. System administrators and storage administrators may need to modify the set of LUNs provisioned to a server. You can change the LUN configuration dynamically, without performing a reconfiguration reboot on the host.
The operations are as follows:
- Removing LUNs dynamically from an existing target ID: Veritas Dynamic Multi-Pathing (DMP) provides a Dynamic Reconfiguration tool
to simplify the removal of LUNs from an existing target ID. Each LUN is unmapped from the host. DMP issues an operating system device scan and cleans up the operating system device tree.
- Adding new LUNs dynamically to a new target ID: the Dynamic Reconfiguration tool simplifies the addition of new LUNs to an
existing target ID. One or more new LUNs are mapped to the host by way of multiple HBA ports. An operating system device scan is issued for the LUNs to be recognized and added to DMP control.
- Replacing LUNs dynamically from an existing target ID: the Veritas Dynamic Multi-Pathing (DMP) provides a Dynamic Reconfiguration
tool to simplify the replacement of new LUNs from an existing target ID. Each LUN is unmapped from the host.DMPissues an operating system device scan and cleans up the operating system device tree.
- Dynamic LUN expansion: many modern disk arrays allow existing LUNs to be resized. The Veritas Volume Manager (VxVM) supports dynamic LUN expansion, by providing a facility to update disk headers and other VxVM structures to match a new LUN size. The device must have a SCSI interface that is presented by a smart switch, smart array or RAID controller.
- Changing the characteristics of a LUN from the array side: some arrays provide a way to change the properties of LUNs. For example, the
EMC Symmetrix array allows write-protected (Read-only), and read-write enabled LUNs. Before changing the properties of a LUN, you must remove the device from Veritas Volume Manager (VxVM) control.
- Replacing a host bus adapter online: Veritas Dynamic Multi-Pathing (DMP) provides a Dynamic Reconfiguration tool to simplify the removal of host bus adapters from an existing system.
For using the Dynamic Reconfiguration tool is sufficient to start the vxdiskadm utility as showed in the pictures below:
From more details, you can consult the following documents for Aix, Linux, HP-UX and Solaris, starting from the version 6.0.1 of Storage Foundation (SF):