InfoScale™ 9.0 Dynamic Multi-Pathing Administrator's Guide - Solaris
- Understanding DMP
- How DMP works
- Disk device naming in DMP
- Setting up DMP to manage native devices
- Using Dynamic Multi-Pathing (DMP) devices with Oracle Automatic Storage Management (ASM)
- Administering DMP
- Managing DMP devices for the ZFS root pool
- Administering DMP using the vxdmpadm utility
- Gathering and displaying I/O statistics
- Specifying the I/O policy
- Administering disks
- Discovering and configuring newly added disk devices
- About discovering disks and dynamically adding disk arrays
- How to administer the Device Discovery Layer
- Changing the disk device naming scheme
- Dynamic Reconfiguration of devices
- About the DMPDR utility
- Reconfiguring a LUN online that is under DMP control using the Dynamic Reconfiguration tool
- Manually reconfiguring a LUN online that is under DMP control
- Event monitoring
- Performance monitoring and tuning
- Appendix A. DMP troubleshooting
- Appendix B. Reference
Displaying the paths to a disk
The vxdisk command is used to display the multi-pathing information for a particular metadevice. The metadevice is a device representation of a physical disk having multiple physical paths through the system's HBA controllers. In Dynamic Multi-Pathing (DMP,) all the physical disks in the system are represented as metadevices with one or more physical paths.
To display the multi-pathing information on a system
- Use the vxdisk path command to display the relationships between the device paths, disk access names, disk media names, and disk groups on a system as shown here:
# vxdisk path
SUBPATH DANAME DMNAME GROUP STATE c1t0d0s2 c1t0d0s2 mydg01 mydg ENABLED c4t0d0s2 c1t0d0s2 mydg01 mydg ENABLED c1t1d0s2 c1t1d0s2 mydg02 mydg ENABLED c4t1d0s2 c1t1d0s2 mydg02 mydg ENABLED . . .
This shows that two paths exist to each of the two disks, mydg01 and mydg02, and also indicates that each disk is in the ENABLED state.
To view multi-pathing information for a particular metadevice
- Use the following command:
# vxdisk list devicename
For example, to view multi-pathing information for c2t0d0s2, use the following command:
# vxdisk list c2t0d0s2
The output from the vxdisk list command displays the multi-pathing information, as shown in the following example:
Device c2t0d0 devicetag c2t0d0 type sliced hostid sys1 . . . Multipathing information: numpaths: 2 c2t0d0s2 state=enabled type=primary c1t0d0s2 state=disabled type=secondary
The numpaths line shows that there are 2 paths to the device. The next two lines in the "Multipathing information" section of the output show that one path is active (state=enabled) and that the other path has failed (state=disabled).
The type field is shown for disks on Active/Passive type disk arrays such as the EMC CLARiiON, Hitachi HDS 9200 and 9500, Sun StorEdge 6xxx, and Sun StorEdge T3 array. This field indicates the primary and secondary paths to the disk.
The type field is not displayed for disks on Active/Active type disk arrays such as the EMC Symmetrix, Hitachi HDS 99xx and Sun StorEdge 99xx Series, and IBM ESS Series. Such arrays have no concept of primary and secondary paths.
- Alternately, you can use the following command to view multi-pathing information:
# vxdmpadm getsubpaths dmpnodename=devicename
For example, to view multi-pathing information for eva4k6k0_6, use the following command:
# vxdmpadm getsubpaths dmpnodename=eva4k6k0_6
Typical output from the vxdmpadm getsubpaths command is as follows:
NAME STATE[A] PATH-TYPE[M] CTLR-NAME ENCLR-TYPE ENCLR-NAME ATTRS ====================================================================================== c0t50001FE1500A8F08d7s2 ENABLED(A) PRIMARY c0 EVA4K6K eva4k6k0 - c0t50001FE1500A8F09d7s2 ENABLED(A) PRIMARY c0 EVA4K6K eva4k6k0 - c0t50001FE1500A8F0Cd7s2 ENABLED SECONDARY c0 EVA4K6K eva4k6k0 - c0t50001FE1500A8F0Dd7s2 ENABLED SECONDARY c0 EVA4K6K eva4k6k0 -