Veritas File System v5.0.1 Administrator's Guide for HP-UX 11i v3 (5900-0082, June 2010)

Tunable I/O parameters
Table 2-1 provides a list and description of these parameters.
Table 2-1
Tunable VxFS I/O parameters
DescriptionParameter
The preferred read request size. The file system uses
this in conjunction with the read_nstream value to
determine how much data to read ahead. The default
value is 64K.
read_pref_io
The preferred write request size. The file system uses
this in conjunction with the write_nstream value
to determine how to do flush behind on writes. The
default value is 64K.
write_pref_io
The number of parallel read requests of size
read_pref_io to have outstanding at one time. The
file system uses the product of read_nstream
multiplied by read_pref_io to determine its read
ahead size. The default value for read_nstream is
1.
read_nstream
The number of parallel write requests of size
write_pref_io to have outstanding at one time.
The file system uses the product of write_nstream
multiplied by write_pref_io to determine when to
do flush behind on writes. The default value for
write_nstream is 1.
write_nstream
53VxFS performance: creating, mounting, and tuning file systems
Tuning I/O