Logical Control Unit
The Logical Control Unit attributes provide performance information for a logical control unit.
All Channels Busy Percent: The percentage of the time all channel paths to this LCU were busy.
Attached Channels: The total number of channel paths that have defined connections to the LCU.
Average Delay Queue: The average number of delayed requests on the control unit header (CU-HDR). This field is calculated as the accumulated Q length minus the number of enqueued requests divided by the number of enqueued requests.
Channel Path I/O Rate: The Channel Path I/O rate for I/Os to this LCU. This field is calculated as the number of I/O operations accepted on this channel path divided by (sample time minus interval start time).
Contention Rate: The rate per second at which the SAP places delayed I/O requests on the CU-HDR for this LCU. This is done when all paths to the subchannel are busy and at least one path to the control unit is busy.
Control Unit Busy Percent: The percentage of requests deferred due to control unit busy.
DCM Channels Attached: The flag indicating that there are DCM channels attached to this LCU.
DCM Channels Channel Path I/O Rate: The Channel Path I/O rate for I/Os to this LCU. This field is computed as the number of I/O operations accepted on this channel path divided by (sample time minus interval start time).
- (the number of deferred I/O requests due to director port busy +
- the number of deferred I/O requests due to control unit busy +
- the number of successful I/O requests on that path) * 100
DCM Channels Defined: The number of DCM channels defined for this LCU.
- (the number of deferred I/O requests due to director port busy +
- the number of deferred I/O requests due to control unit busy +
- the number of successful I/O requests on that path) * 100
DCM Channels Maximum: The maximum number of DCM channels used for this LCU.
DCM Channels Minimum: The minimum number of DCM channels used for this LCU.
Director Port Busy Percent: The percentage the director port is busy. This field indicates director port contention. This value is the number of times an I/O request was deferred because the director port was busy during the measurement interval.
High DFW Retry Percent: The highest DFW retry percentage of any volume on this LCU.
High Volume MSR: The highest MSR (millisecond response time) of any volume on this LCU.
High Volume Utilization: The highest percentage busy of any volume on this LCU.
I/O Per Second: The channel Path I/O Rate for I/Os to this.
LCU Hex Number: The character representation to the hexadecimal number of this LCU.
LCU Number: The HCD-assigned number for this logical control unit. An LCU is a logical representation of either a single control unit, with or without attached devices, or a group of control units that share devices.
Low Read Hit Percent: The lowest read hit percentage of any volume on this LCU.
Low Write Hit Percent: The lowest write hit percentage of any volume on this LCU.
Managed System: The SMS name of this system.
Maximum HyperPAV Unavailable Alias Percent: The maximum percent of the number of I/Os that could not start for a control unit because a HyperPAV alias was not available.
Maximum I/Os Queued: The maximum number of I/Os queued for a control unit.
NonSMS Volumes: The total number of nonSMS-managed volumes on this LCU.
PDS Record: A single record of trend data retrieved from persistent data store.
SMS Volumes: The total number of SMS-managed volumes on this LCU.
Time Stamp: The date and time associated with this row.
Total Volumes: The count of the total number of volumes in this LCU.