Enabling the request histogram facility
The rhist on request enables the request histogram facility.
When rhist on is invoked the first time, this request creates the necessary data objects to support histogram data gathering. This request may be combined with rhist off (or another rhist on) as often as desired. If there are no mounted file systems at the time rhist on is issued, the facility is still enabled. The response is a single string.
Table 1 describes the keywords for the rhist on response, in the order that they appear in the output. These keywords are used only when mmpmon is invoked with the -p flag.
| Keyword | Description |
|---|---|
| _n_ | IP address of the node responding. This is the address by which GPFS knows the node. |
| _nn_ | The hostname that corresponds to the IP address (the _n_ value). |
| _req_ | The action requested. In this case, the value is on. |
| _rc_ | Indicates the status of the operation. |
| _t_ | Indicates the current time of day in seconds (absolute seconds since Epoch (1970)). |
| _tu_ | Microseconds part of the current time of day. |
An _rc_ value of 16 indicates that the histogram operations lock is busy. Retry the request.