Migration from Legacy to Agile Naming Model in VxVM 5.
Abstract This white paper discusses the migration of VxVM volume group configurations from legacy to the agile naming model. The agile naming model is a new representation for mass storage devices, introduced in HP-UX 11i v3. The legacy naming model is the naming model used in releases prior to HP-UX 11i v3. This document is intended for system administrators or operators who have experience with both HP-UX and VxVM.
1. Legacy and Agile Naming Models In versions prior to HP-UX 11i v3, the Device Special Files (DSFs) of mass storage devices were bound to the path of the device. This representation of mass storage devices still exists in HP-UX 11i v3, and is referred as the legacy view. HP-UX 11i v3 introduces a new representation for mass storage devices called the agile view.
disk disk 8 64000/0xfa00/0x3 esdisk CLAIMED 9 64000/0xfa00/0x5 esdisk CLAIMED DEVICE DEVICE HP DVD-ROM 305 HP 73.4GST373307LC 2. VxVM 5.0 Support for Dual Naming In HP-UX 11i v3 release, VxVM 5.0 supports both legacy and persistent DSFs. VxVM disk groups can be configured using both styles of DSFs. On a system, disk groups can either use legacy DSFs or persistent DSFs.
3. Migrating to Agile Naming Model The migration of volume groups from legacy DSF naming model to persistent DSF naming model can be achieved by using the following command. vxddladm set namingscheme=osn mode=new The execution of the above command would result in VxVM 5.0 migrating from Legacy Naming Model to Agile Naming Model. The mode option applies to the OS native naming scheme only. For ease of use VxVM 5.0 supports both Agile and Legacy Naming model.
The execution of the above command would result in VxVM 5.0 operating in legacy mode. # vxdmpadm getlungroup dmpnodename=c9t6d0 NAME STATE ENCLR-TYPE PATHS ENBL DSBL ENCLR-NAME ========================================================== c9t6d0 ENABLED Disk 1 1 0 Disk # vxdmpadm getlungroup dmpnodename=disk9 NAME STATE ENCLR-TYPE PATHS ENBL DSBL ENCLR-NAME ========================================================== c9t6d0 ENABLED Disk 1 1 0 Disk c.
A Typical Migration Operation STEP 1 : List all the volume groups configured with Legacy DSF’s. Only the volume groups configured with legacy DSF must be migrated. # vxdisk list DEVICE TYPE DISK c0t5d0 auto:FS_wholedisk c0t6d0 auto:LVM c6t6d0 auto:FS_wholedisk c9t6d0 auto:cdsdisk c9t6d0 c12t0d0 auto:cdsdisk c12t0d0 GROUP vxvmdg testdg STATUS FS_wholedisk LVM FS_wholedisk online online STEP 2 : Verify that all the disk groups to be migrated are online.
NOTE: Device naming change will take effect irrespective of whether the disk group is imported or not, whether volume is shared or not, whether all nodes have disk groups imported or not and whether it is CVM environment or not. Advantages of Migrating to the Agile mode In Agile mode devices are identified by the actual object, not by a hardware path to the object. Paths to a device can change dynamically, and multiple paths to a single device can be transparently treated as a single virtualized path.
Glossary Agile Addressing The ability to address a LUN with the same device special file regardless of the physical location of the LUN or the number of paths leading to it. The DSF for a LUN remains the same even if the LUN is moved from one HBA to another, moved from one switch or hub port to another, presented using a different target port to the host, or configured with multiple hardware paths. This is also referred to as persistent LUN binding.
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