LCTL-GET_PARAM(8)

NAME
lctl-get_param - retrieve configuration parameters

SYNOPSIS
lctl get_param [-F] [-n|-N] [-R] <parameter...>

DESCRIPTION
Get the value of the named Lustre or LNet parameter on the local node. Parameter names consist of one or more components, separated by a '.' (period). Each component may be specified by plain text or by a wildcard in the glob(7) format. When wildcards are used, more than one parameter may match and be returned. Parameters are often, but not always, of the form obd_name.obd_instance.parameter_name, where obd_name is one of the OBD object types, like ldlm, llite, lmv, lov, mdc, osc, etc., and obd_instance is the name of a Lustre device, like testfs-OST0000, but may be a specific component, or contain wildcards to match some or all devices on the node. Many parameters are readable as a regular user, though some of them are accessible only by the root user for security or implementation reasons.

OPTIONS

-F  Append a '/', '@', or '=' suffix for directories, symlinks, and writeable parameters, respectively. lctl get_param -NF is equivalent to lctl list_param -F.

-n  Print only the parameter value and not parameter name. This may be confusing if multiple parameter names are specified, as the parameters are not identified, and may not be returned in the order that they are specified.

-N  Print only matched parameter names and not the values. This is especially useful when using patterns.

-R  Recursively show all of the parameter names below the specified name.

-y  Some paramters can be presented in a YAML format but are not by default. This will format the parameter data in YAML. If the YAML provides a source: field it can be suppressed with the -n option.

EXAMPLES
$ lctl get_param osc.*.max_pages_per_rpc
osc.myth-OST0000-osc-ffff8803c9c0f000.max_pages_per_rpc=1024
osc.myth-OST0001-osc-ffff8803c9c0f000.max_pages_per_rpc=1024
osc.testfs-OST0000-osc-ffff8803c9c0f000.max_pages_per_rpc=1024
osc.testfs-OST0001-osc-ffff8803c9c0f000.max_pages_per_rpc=1024
osc.testfs-OST0002-osc-ffff8803c9c0f000.max_pages_per_rpc=1024
$ lctl get_param -n debug
super warning dlmtrace error emerg rpctrace vfstrace config console
$ lctl get_param {mdc,osc}.testfs-*.max_rpcs_in_flight
mdc.testfs-MDT0000-mdc-ffff8803c9c0f000.max_rpcs_in_flight=16
osc.testfs-OST0000-osc-ffff8803c9c0f000.max_rpcs_in_flight=8
osc.testfs-OST0001-osc-ffff8803c9c0f000.max_rpcs_in_flight=8
osc.testfs-OST0002-osc-ffff8803c9c0f000.max_rpcs_in_flight=8
$ lctl get_param -n devices
 0 UP osd-ldiskfs MGS-osd MGS-osd_UUID 4
$ lctl get_param -y devices
devices:
- index: 0
  status: UP
  type: osd-ldiskfs
  name: MGS-osd
  uuid: MGS-osd_UUID
  refcount: 4

SEE ALSO
lustre(7), lctl(8), lctl-list_param(8), lctl-set_param(8)