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Chapter 6 HPSS Configuration
HPSS Installation Guide September 2002 309
Release 4.5, Revision 2
VV Block Size The size of the logical data
block on the new virtual
volume.
A 32-bit integer value. First multiple
of Media
Block Size
which equals
or exceeds
1MB.
Advice: The VV Block Size chosen will determine the performance characteristics of
the virtual volume. This value must meet the following constraining requirements:
(1) it must be an integer multiple of the Media Block Size. (2) For tape, it must be
an even divisorof the virtualvolume section size(Media Block Size *Blocks Between
Tape Marks). For example, if the Media Block Size is 64 KB, and the Blocks Between
Tape Marks is 512, the virtual volume section size is 32 MB. The VV Block Size
could be 64 K, 128 K, 256 K, or larger, but not 192 K. See Sections 2.9.1.2 and
2.9.1.3 for more details on selecting a good value for VV Block Size.
PV Estimated Size The estimated amount of
data that can be written on
the tape physical volume.
Any positive 64-bit integer value. Based on
selected
Media Type
Advice: See Section 2.9.1.10 for considerations on selecting a good value for PV
Estimated Size.
PV Size The size of a disk PV in
the storage class, in bytes.
Any positive non-zero 64-bit value.
Must be a multiple of the VV Block
Size and the Media Block Size.
See section
2.9.1.10 for
considerations
on selecting
disk PV Size
values.
Stripe Width The number of physical
volumes in a virtual
volume.
For tape: 1 - 16
For disk: 1 - 256
1.
Stripe Length The number of bytes in a
stripe.
This value is calculated by SSM. It
is the product of the specified VV
Block Size and Stripe Width fields.
Same as VV
Block Size.
Device I/O Rate The approximate data
transfer speed, in kilobytes
per second, which can be
achieved by devices
corresponding to “Media
Type”. For Tape, this field
is used in calculating a
reasonable setting for
“Blocks Between Tape
Marks” (see below). For
Disk, this field is mostly
informational.
Any positive 32-bit integer value
The value should, however, be as
close as possible to the actual I/O
speed of the device.
Based on
selected
Media Type.
Table 6-11 Storage Class Configuration Variables (Continued)
Display Field Name Description Acceptable Values
Default
Value