eG Monitoring
 

Measures reported by HpP2kHostPortTest

A Host Port is a port on a controller module that interfaces with a host computer, either directly or through a network switch. Since host ports facilitate host-controller interactions, any slowdown in I/O processing that a user may complain of can be attributed to an overloaded port or poor I/O performance of a port. To be able to proactively detect such problems with a port and take adequate measures to curb them, administrators need to keep an eye on the level of I/O activity on each host port, measure the I/O processing ability of the ports, and identify the 'weak links' of the storage environment - i.e., isolate those host ports that are either overloaded or are slow in processing requests. Such host ports can be identified using the HpP2kHostPortTest test.

For every host port on a controller, this test reports the rate at which the port services read and write requests and reveals the count of requests that are pending processing by the port. This way, the test clearly points administrators to a probable overload or a processing delay with the host ports.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
bytes_per_sec Indicates the rate at which data is transmitted through this host port during the last measurement period. MB/Sec This is a good indicator of the load on the port. You can compare the value of this measure across host ports to figure out whether the load has been distributed uniformly across all ports or a few ports are overloaded. In case of the latter, you may have to fine-tune the load-balancing algorithm used.
iops Indicates the rate at which the I/O operations were performed through this host port during the last measurement period. IOPS This measure serves as a good indicator of the I/O processing ability of the host port. A consistent drop in this value is hence a cause for concern, as it indicates a processing slowdown.
num_reads Indicates the rate at which the read operations were performed through this host port during the last measurement period. Reads/Sec Ideally, the value of this measure should be high. A steady dip in this measure value could indicate a potential reading bottleneck. By comparing the value of this measure across host ports, you can quickly identify that host port which is the slowest in processing read requests.
num_writes Indicates the rate at which the write operations were performed through this host port during the last measurement period. Writes/Sec Ideally, the value of this measure should be high. A steady dip in this measure value could indicate a potential writing bottleneck. By comparing the value of this measure across host ports, you can quickly identify that host port which is the slowest in processing write requests.
data_read Indicates the rate at which the data was read through this host port during the last measurement period. MB/Sec Comparing the value of these measures across the host ports will clearly indicate which host port is the busiest in terms of data transmission - it could also shed light on irregularities in load balancing across the host ports.
data_writes Indicates the rate at which the data was written through this host port during the last measurement period. MB/Sec
queue_depth Indicates the number of pending I/O operations that are currently being serviced through this host port. Number A consistent rise in the value of this measure indicates a processing bottleneck at the port that is causing I/O requests to queue up.