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Enabling Cached Quick I/O

Caching for Quick I/O files can be enabled online when the database is running.

See the vxtunefs(1M) and qioadmin(1) manual pages.

  Note   Quick I/O must be enabled on the file system for Cached Quick I/O to operate.

 To enable caching

1. Set the qio_cache_enable parameter of vxtunefs to enable caching on a file system.
2. Enable the Cached Quick I/O feature for specific files using the qioadmin command.

Enabling Cached Quick I/O for file systems

Caching is initially disabled on a file system. You enable Cached Quick I/O for a file system by setting the qio_cache_enable option of the vxtunefs command after the file system is mounted.

  Note   The vxtunefs command enables caching for all the Quick I/O files on the file system.

The following example enables Cached Quick I/O for the file system
/database01.

 To enable Cached Quick I/O for a file system

1. Enable Cached Quick I/O:

# vxtunefs -s -o qio_cache_enable=1 /database01

/database01 is a VxFS file system containing the Quick I/O files.

2. If desired, make this setting persistent across mounts by adding a file system entry in the file /etc/vx/tunefstab:

/dev/vx/dsk/datadg/database01 qio_cache_enable=1
/dev/vx/dsk/datadg/database02 qio_cache_enable=1

See the tunefstab(4) manual page.

Manipulating Cached Quick I/O settings for individual files

A Quick I/O file's Cached Quick I/O settings are manipulated with the vxtunefs utility and the qioadmin command.

See the vxtunefs(1M) and qioadmin(1) manual pages.

  Note   The cache advisories operate only if Cached Quick I/O is enabled for the file system. If the qio_cache_enable flag is zero, Cached Quick I/O is OFF for all the files in that file system even if the individual file cache advisory for a file is ON.

 To enable caching on a file

• Enable caching on a file:

$ qioadmin -S filename=on mount_point

 To disable caching on a file

• Disable caching on a file:

$ qioadmin -S filename=off mount_point

 To make the caching setting persistent across mounts

• Create a qiotab file, /etc/vx/qioadmin, to list files and their caching advisories. Based on the following example, the file /database/sell.dbf will have caching turned on whenever the file system /database is mounted:

device=/dev/vx/dsk/datadg/database01
dates.dbf,off
names.dbf,off
sell.dbf,on

 To check on the current cache advisory settings for a file

• Check the current cache advisory settings:

$ qioadmin -P filename mount_point

filename,OFF

 To check the setting of the qio_cache_enable flag for a file system

• Check the setting of the qio_cache_enable flag:

$ vxtunefs -p /database01

qio_cache_enable = 1

Check the setting of the flag qio_cache_enable using the vxtunefs command, and the individual cache advisories for each file, to verify caching.