HP-UX 11i v3 Installation and Update Guide, March 2010

HP-UX 11i v3 device special files (DSF)
In a similar way to hardware paths, there are two types of Device Special Files (DSFs) for mass
storage: legacy DSFs and persistent DSFs. Both can be used to access a given mass storage device
independently, and can coexist on a given system.
DSFs: installing and updating
If you cold-install HP-UX 11i v3, both legacy and persistent DSFs are automatically created. By
default, the installation process will configure system devices like the boot, root, swap, and dump
devices to use persistent DSFs. This means that configuration files such as/etc/fstab, /etc/
lvmtab, and others will contain references to persistent DSFs.
When you update from HP-UX 11i v2 to 11i v3, existing legacy DSFs are retained and persistent
DSFs will be created. Configuration files are not updated to use agile DSFs. HP-UX will continue
to use the existing legacy DSFs referenced in configuration files.
Legacy DSFs are completely backward compatible, and will not be affected by any persistent
DSFs on the same server. A device can be simultaneously accessed via legacy and persistent
DSFs.
For more information, including definitions of legacy and persistent, see “The Next Generation
Mass Storage Stack: HP-UX 11i v3” and “HP-UX 11i v3 Persistent DSF Migration Guide”
(www.hp.com/go/hpux-core-docs).
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