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tunefstab - VxFS file system tuning parameters table




The tunefstab file contains tuning parameters for Veritas File Systems. tunefstab sets the tuning parameters for mounted file systems by processing command line options or by reading parameters in the tunefstab file.

Each entry in tunefstab is a line of fields in one of the following formats:

block_device tunefs options

system_default tunefs options

block_device is the name of the device on which the file system is mounted. If there is more than one line that specifies options for a device, each line is processed and the options are set in order.

In place of block_device, system_default specifies tunables for each device to process. If there is an entry for both a device and system_default, the device value takes precedence.

Lines in tunefstab that start with the pound (#) character are treated as comments and ignored.

The tunefs options correspond to the tunable parameters that vxtunefs and mount_vxfs set on the file system. Each option in this list is a name=value pair. Separate the options by commas, with no spaces or tabs between the options and commas.

See the vxtunefs(1M) manual page for a description of the supported options.


If you have a four column striped volume, /dev/vx/dsk/datadg/db03, with a stripe unit size of 128 kilobytes per disk, set the read_pref_io and read_nstream parameters 128 and four, respectively. You can do this in two ways:

/dev/vx/dsk/datadg/db03 read_pref_io=128k,read_nstream=4


/dev/vx/dsk/datadg/db03 read_pref_io=128k

/dev/vx/dsk/datadg/db03 read_nstream=4

To set the discovered direct I/O size lower so that it is always lower than the default, add the following line to the /etc/vx/tunefstab file:

/dev/dsk/c3t1d0s4 discovered_direct_iosz=128K



Default tunefstab file.


mkfs_vxfs(1M), mount(1M), vxtunefs(1M)

Veritas File System Administrator's Guide