Overview: The Next Generation Mass Storage Stack (September 2009)

In addition, there are four appendixes:
Summary of Changes
A short summary of the user-visible changes to commands, device file names, and tunables.
Using ioscan
A sample output of the ioscan command using several of the new options.
Using scsimgr
The most common examples of setting device tunables.
Interpreting lunpath hardware paths
How to interpret the address elements for the new lunpath hardware paths.
Features of the Next Generation Mass Storage Stack
This section describes the new features of the next generation mass storage stack and the commands that changed
due to those features. For benefits associated with these features, refer to Benefits of Migration
.
Scalability
The next generation mass storage stack increases the server mass storage capacities in the following areas:
Number of I/O busses
The number of I/O busses on HP-UX 11i v1 and v2 is limited to 256 bus instances. This
limit has been removed for HP-UX 11i v3.
Note: Persistent device special files (DSFs), described in Agile Addressing
, must be
used to access any bus with an instance greater than 255.
Number of Logical Units (LUNs) supported
In previous releases, the supported number of LUNs was based on the number of active
LUN paths per server. On HP-UX 11i v3, 16384 LUNs are supported.
LUN Size The I/O system supports LUNs greater than two TB in size.
Number of distinct I/O paths to a LUN
Previously, a LUN could have up to eight physical I/O paths. For HP-UX 11i v3, this
increases to 32 I/O paths per LUN, up to a maximum of 65536 LUN paths per server.
File system size File systems can be as large as eight EB (8192 TB). This limit is constrained by any
volume manager and file system type size restrictions; for example, LVM supports a
maximum volume size of 16 TB, so the maximum file system size under LVM is 16 TB.
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