NAME

DESCRIPTION

Entry points are the leaves of the CTL namespace structure. Each entry point can read from the internal state, write to the internal state, exec a function or a combination of these operations.

The entry points are listed in the following format:

name | r(ead)w(rite)x(ecute) | global/- | read argument type | write argument type | exec argument type | config argument type

A description of pmem_ctl functions can be found on the following manual pages: libpmemblk_ctl_get(3), libpmemlog_ctl_get(3), libpmemobj_ctl_get(3)

CTL EXTERNAL CONFIGURATION

The first method is to load a configuration directly from the PMEMBLK_CONF/ PMEMLOG_CONF/ PMEMOBJ_CONF environment variable. A properly formatted ctl config string is a single-line sequence of queries separated by `;':

query0;query1;...;queryN

    

A single query is constructed from the name of the ctl write entry point and the argument, separated by `=':

entry_point=entry_point_argument

    

The entry point argument type is defined by the entry point itself, but there are three predefined primitives:

*) integer: represented by a sequence of [0-9] characters that form
    a single number.
*) boolean: represented by a single character: y/n/Y/N/0/1, each
    corresponds to true or false. If the argument contains any
    trailing characters, they are ignored.
*) string: a simple sequence of characters.

    

There are also complex argument types that are formed from the primitives separated by a `,':

first_arg,second_arg

    

In summary, a full configuration sequence looks like this:

(first_entry_point)=(arguments, ...);...;(last_entry_point)=(arguments, ...);

    

As an example, to set both prefault at_open and at_create variables:

PMEMBLK_CONF="prefault.at_open=1;prefault.at_create=1"

    

The second method of loading an external configuration is to set the PMEMBLK_CONF_FILE/ PMEMLOG_CONF_FILE/ PMEMOBJ_CONF_FILE environment variable to point to a file that contains a sequence of ctl queries. The parsing rules are all the same, but the file can also contain white-spaces and comments.

To create a comment, simply use `#' anywhere in a line and everything afterwards, until a new line, will be ignored.

An example configuration file:

#########################
# My pmemblk configuration
#########################
#
# Global settings:
prefault. # modify the behavior of pre-faulting
    at_open = 1; # prefault when the pool is opened
prefault.
    at_create = 0; # but don't prefault when it's created
# Per-pool settings:
# ...

    

SEE ALSO