Device groups

Adding devices to a device group

IOPT_GRP_ADD adds logical devices to a device group. If a group with the specified name does not exist, it is configured. Only devices which are activated (either beforehand or subsequently) for IOPT using IOPT_DEV_ADD are also monitored by IOPT. Merely defining a device group is not enough to activate it.

IOPT monitors a device group like a device, in other words it examines the utilization of the entire group. For example, all logical devices which are assigned to a physical disk can form a device group. In this way IOPT detects I/O bottlenecks on the disk even if the utilization threshold values have not yet been exceeded for individual logical devices.

IOPT_GRP_ADD                                                                                                                                     

IOPT_GRP_xxx_ADD=D-R(mn1.mn2)

xxx	Three-digit numeric name of the device group. Value range: 000 < x <= 255
D-R(mn1,mn2)
	All devices with mnemonic names from mn1 to mn2 are added to the group. If mn1 and mn2 are identical, only one device is added to the group.

Removing devices from a device group

IOPT_GRP_REM removes logical devices from a device group. When the last device is removed from a group, the group is also deleted.

IOPT_GRP_REM                                                                                                                                     

IOPT_GRP_xxx_REM=ALL

IOPT_GRP_xxx_REM=D-R(mn1,mn2)

xxx	Three-digit numeric name of the device group. Value range: 000 < x <= 255
ALL	All devices in the group are removed. The group is deleted.
D-R(mn1,mn2)
	All devices with mnemonic names from mn1 to mn2 are removed from the group. If mn1 and mn2 are identical, only one device is removed from the group.

 

Querying devices of a device group

IOPT_GRP_ADD? displays a list of all the devices which belong to a device group.

IOPT_GRP_ADD?                                                                                                                                  

IOPT_GRP_xxx_ADD?mask

xxx	Three-digit numeric name of the device group. Value range: 000 < x <= 255
mask	Complete or masked specification of a mnemonic device name. The following specifications are possible:
	*	All devices in the group are listed.
	n*	All devices in the group whose names begin with n are listed.
	nm*	All devices in the group whose names begin with nm are listed.
	nml*	All devices in the group whose names begin with nml are listed.
	nmlo	The device in the group with the name nmlo is listed.