Before you can investigate server latency, you need to have created an HTTP Analytics
profile that is logging statistics internally on the BIG-IP system. The HTTP Analytics
profile must be associated with one or more virtual servers, or with an iApps
You can review statistics concerning server
latency on the HTTP Overview chart. Server latency is
how long it takes (in milliseconds ) from the time a request reaches the BIG-IP system,
for it to proceed to the web application server, and return a response to the BIG-IP
On the Main tab, click
The Overview screen opens and displays current HTTP statistics averaged
over the last hour. On the screen, you can see time controls on the top, charts
on the left, and a list of dimensions on the right.
Scroll down to the Avg Server Latency chart.
The chart shows the server
latency for all applications and virtual servers associated with all Analytics
To view server latency for a specific application,
from the dimensions on the right, expand Applications and select only
latency only for the selected application.
To see more detailed latency statistics for any
expanded dimensions, click the handle at the top of the dimensions column,
Tables containing detailed
statistics for the items in the dimensions are displayed.
In the table, hover over the headings to see the
full names of the columns, and view the data.
Avg Server Latency (ms)
shows the average server latency in milliseconds.
Min Server Latency (ms)
shows the minimum server latency in milliseconds.
Max Server Latency (ms)
shows the maximum server latency in milliseconds.
To view the graphic charts and dimensions again,
click the handle on the top left of the table.
To view server latency for a specific virtual
server, from the dimensions on the right, expand Virtual Servers and select
only that virtual server.
You can clear all filter selections or those for a dimension.
If further investigation is needed, select other
dimensions to show latency for other entities, for example, specific pool
members, URLs, countries, or client IP addresses.
you are concerned about server latency, you can configure the HTTP Analytics profile
so that it sends an alert when the average server latency exceeds a number of
milliseconds for some period of time. See Getting an
alert when server latency is high.