InfoScale™ 9.0 Storage Foundation Administrator's Guide - AIX
- Section I. Introducing Storage Foundation
- Overview of Storage Foundation
- How Dynamic Multi-Pathing works
- How Volume Manager works
- How Volume Manager works with the operating system
- How Volume Manager handles storage management
- Volume layouts in Veritas Volume Manager
- Online relayout
- Volume resynchronization
- Dirty region logging
- Volume snapshots
- FastResync
- How VxVM handles hardware clones or snapshots
- How Veritas File System works
- Section II. Provisioning storage
- Provisioning new storage
- Advanced allocation methods for configuring storage
- Customizing allocation behavior
- Using rules to make volume allocation more efficient
- Understanding persistent attributes
- Customizing disk classes for allocation
- Specifying allocation constraints for vxassist operations with the use clause and the require clause
- Creating volumes of a specific layout
- Customizing allocation behavior
- Creating and mounting VxFS file systems
- Creating a VxFS file system
- Mounting a VxFS file system
- tmplog mount option
- ioerror mount option
- largefiles and nolargefiles mount options
- Resizing a file system
- Monitoring free space
- Extent attributes
- Section III. Administering multi-pathing with DMP
- Administering Dynamic Multi-Pathing
- Discovering and configuring newly added disk devices
- About discovering disks and dynamically adding disk arrays
- How to administer the Device Discovery Layer
- Administering DMP using the vxdmpadm utility
- Gathering and displaying I/O statistics
- Specifying the I/O policy
- Discovering and configuring newly added disk devices
- Dynamic Reconfiguration of devices
- Reconfiguring a LUN online that is under DMP control using the Dynamic Reconfiguration tool
- Manually reconfiguring a LUN online that is under DMP control
- Managing devices
- Displaying disk information
- Changing the disk device naming scheme
- Adding and removing disks
- Event monitoring
- Administering Dynamic Multi-Pathing
- Section IV. Administering Storage Foundation
- Administering sites and remote mirrors
- About sites and remote mirrors
- Fire drill - testing the configuration
- Changing the site name
- Administering the Remote Mirror configuration
- Failure and recovery scenarios
- Administering sites and remote mirrors
- Section V. Optimizing I/O performance
- Section VI. Using Point-in-time copies
- Understanding point-in-time copy methods
- When to use point-in-time copies
- About Storage Foundation point-in-time copy technologies
- Volume-level snapshots
- Storage Checkpoints
- About FileSnaps
- About snapshot file systems
- Administering volume snapshots
- Traditional third-mirror break-off snapshots
- Full-sized instant snapshots
- Creating instant snapshots
- Adding an instant snap DCO and DCO volume
- Controlling instant snapshot synchronization
- Creating instant snapshots
- Cascaded snapshots
- Adding a version 0 DCO and DCO volume
- Administering Storage Checkpoints
- Storage Checkpoint administration
- Administering FileSnaps
- Administering snapshot file systems
- Understanding point-in-time copy methods
- Section VII. Optimizing storage with Storage Foundation
- Understanding storage optimization solutions in Storage Foundation
- Migrating data from thick storage to thin storage
- Maintaining Thin Storage with Thin Reclamation
- Reclamation of storage on thin reclamation arrays
- Identifying thin and thin reclamation LUNs
- InfoScale 4K sector device support solution
- Section VIII. Maximizing storage utilization
- Understanding storage tiering with SmartTier
- Creating and administering volume sets
- Multi-volume file systems
- Features implemented using multi-volume file system (MVFS) support
- Adding a volume to and removing a volume from a multi-volume file system
- Volume encapsulation
- Load balancing
- Administering SmartTier
- About SmartTier
- Placement classes
- Administering placement policies
- File placement policy rules
- Multiple criteria in file placement policy rule statements
- Using SmartTier with solid state disks
- Sub-file relocation
- Administering hot-relocation
- How hot-relocation works
- Moving relocated subdisks
- Compressing files
- About compressing files
- Use cases for compressing files
- Section IX. Administering and protecting storage
- Administering VxVM volumes as paging devices
- Managing volumes and disk groups
- Rules for determining the default disk group
- Moving volumes or disks
- Monitoring and controlling tasks
- Performing online relayout
- Adding a mirror to a volume
- Managing disk groups
- Disk group versions
- Displaying disk group information
- Importing a disk group
- Moving disk groups between systems
- Importing a disk group containing hardware cloned disks
- Handling conflicting configuration copies
- Destroying a disk group
- Backing up and restoring disk group configuration data
- Managing plexes and subdisks
- Decommissioning storage
- Using DMP with a SAN boot disk
- Configuring DMP for SAN booting
- Administering the root volume group (rootvg) under DMP control
- Extending an LVM rootvg that is enabled for DMP
- Quotas
- Using Veritas File System quotas
- File Change Log
- Section X. Reference
- Appendix A. Reverse path name lookup
- Appendix B. Tunable parameters
- Tuning the VxFS file system
- Methods to change Dynamic Multi-Pathing tunable parameters
- Tunable parameters for VxVM
- Methods to change Veritas Volume Manager tunable parameters
- Appendix C. Command reference
- Appendix D. Executive Order logging
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 hdisk1 hdisk1 mydg01 mydg ENABLED hdisk9 hdisk9 mydg01 mydg ENABLED hdisk2 hdisk2 mydg02 mydg ENABLED hdisk10 hdisk10 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 hdisk18, use the following command:
# vxdisk list hdisk18
The output from the vxdisk list command displays the multi-pathing information, as shown in the following example:
Device: hdisk18 devicetag: hdisk18 type: simple hostid: sys1 . . . Multipathing information: numpaths: 2 hdisk18 state=enabled type=primary hdisk26 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 emc_clariion0_17, use the following command:
# vxdmpadm getsubpaths dmpnodename=emc_clariion0_17
Typical output from the vxdmpadm getsubpaths command is as follows:
NAME STATE[A] PATH-TYPE[M] CTLR-NAME ENCLR-TYPE ENCLR-NAME ATTRS =========================================================================== hdisk107 ENABLED(A) PRIMARY fscsi1 EMC_CLARiiON emc_clariion0 - hdisk17 ENABLED SECONDARY fscsi0 EMC_CLARiiON emc_clariion0 - hdisk2 ENABLED SECONDARY fscsi0 EMC_CLARiiON emc_clariion0 - hdisk32 ENABLED(A) PRIMARY fscsi0 EMC_CLARiiON emc_clariion0 -