DMP Coexistence with EMC PowerPath
With this release of VxVM, DMP can coexist with PowerPath, and supports the inclusion of PowerPath-controlled devices with shared disk groups in clusters. Depending on the scenario, you might need to install the EMC CX600 array support library (ASL) and its associated array policy module (APM). To use DMP with PowerPath, you should be aware of the following scenarios.
- If you are installing VxVM 4.1 and PowerPath is installed, you do not need to install the CX600 ASL and its associated APM. The array must be configured in explicit failover mode.
- If you are installing VxVM 4.1 and PowerPath is not installed, you must install the CX600 ASL and its associated APM. The array can be in any mode.
The following table lists these scenarios and the required array modes:
| PowerPath
|
DMP
|
Array mode
|
|---|
Installed; the array is a CX600
|
The libvxemc.so ASL handles EMC arrays and DGC claiming internally. PP handles fail-over.
There is no need to install either the CX600 ASL or CX600 APM.
|
Explicit failover
|
Not installed; the array is a CX600
|
DMP handles multipathing.
Both the CX600 ASL and CX600 APM must be installed.
|
-
|
Not installed; the array is not a CX600
|
The libvxemc.so ASL handles the EMC Symmetrix array. DMP handles multipathing.
|
-
|
Note
If you are upgrading a system to VxVM 4.1, which has PowerPath installed, and the CX600 ASL and its associated CX600 APM are also installed, you must uninstall both the CX600 ASL and APM, otherwise the CX600 will claim the disks and the PowerPath discs will not be identified.
If you are upgrading a system to VxVM 4.1, which does not have PowerPath installed, but the CX600 ASL and its APM are both installed, then the CX600 ASL and its associated APM should not be uninstalled.
|
