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

VxVM queries

VxVM receives the following queries during configuration:

■ The file system queries VxVM to determine the geometry of the underlying

volume and automatically sets the I/O parameters.

Note: When using file systems in multiple volume sets, VxFS sets the VxFS

tunables based on the geometry of the first component volume (volume 0) in

the volume set.

■ The mount command queries VxVM when the file system is mounted and

downloads the I/O parameters.

If the default parameters are not acceptable or the file system is being used without

VxVM, then the /etc/vx/tunefstab file can be used to set values for I/O

parameters. The mount command reads the /etc/vx/tunefstab file and downloads

any parameters specified for a file system. The tunefstab file overrides any values

obtained from VxVM. While the file system is mounted, any I/O parameters can

be changed using the vxtunefs command which can have tunables specified on

the command line or can read them from the /etc/vx/tunefstab file.

See the vxtunefs(1M) and tunefstab(4) manual pages.

The vxtunefs command can be used to print the current values of the I/O

parameters.

To print the values, type the following command:

# vxtunefs -p mount_point

The following is an example tunefstab file:

/dev/vx/dsk/userdg/netbackup

read_pref_io=128k,write_pref_io=128k,read_nstream=4,write_nstream=4

/dev/vx/dsk/userdg/metasave

read_pref_io=128k,write_pref_io=128k,read_nstream=4,write_nstream=4

/dev/vx/dsk/userdg/solbuild

read_pref_io=64k,write_pref_io=64k,read_nstream=4,write_nstream=4

/dev/vx/dsk/userdg/solrelease

read_pref_io=64k,write_pref_io=64k,read_nstream=4,write_nstream=4

/dev/vx/dsk/userdg/solpatch

read_pref_io=128k,write_pref_io=128k,read_nstream=4,write_nstream=4

VxFS performance: creating, mounting, and tuning file systems

Tuning I/O