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HP-UX 11i v3 Installation and Update Guide, February 2007 (Initial Release)

ManualsBrandsHP ManualsSoftwareHP-UX 11i v3 Virtual Server Operating Environment (VSE-OE) LTU
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Choosing an Installation Method
New Mass Storage Stack for HP-UX 11i v3
Chapter 3 47
HP-UX 11i v3 Device Special File (DSF)
In a similar way to hardware paths, there are two types of 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. These DSFs are described below.
• A legacy device special file was the only type of mass storage DSF in
releases prior to HP-UX 11i v3, so it is associated with the legacy
view. It is locked to a particular physical hardware path, or lunpath,
and does not support agile addressing. Each lunpath requires a
different DSF, so a multi-pathed LUN has multiple DSFs, one for
each lunpath.
• A persistent device special file is associated with a LUN hardware
path, and is seen in the agile view. Because it is based on the LUN
hardware path, rather than the lunpath, it transparently supports
agile addressing and multipathing. Like the LUN hardware path,
the binding of device special file to device persists across reboots, but
is not guaranteed to persist across installations.
Device Files: 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.
If you update from HP-UX 11i v2 to 11i v3, existing legacy DSFs are
retained, and persistent DSFs will be created.
In addition, 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 on the new mass storage stack, see the whitepaper
called, “The Next Generation Mass Storage Stack: HP-UX 11i v3” at:
http://docs.hp.com/