track of a number of metrics and statistics about its own performance and
raises alarms when certain thresholds are exceeded. The system also protects
itself by rejecting requests that would cause it to exceed its critical
capacity limits. When the node is at capacity, new recordings are redirected to
other nodes (if available) or rejected and lost.
is always considered to be the highest priority operation, MediaSense reserves
a certain amount of capacity specifically for that purpose, electing to reject
media output requests while still continuing to accept new recording requests.
Media output requests (such as live monitoring, playback, raw download and .mp4
or .wav conversion) result in 503 responses when the node is at capacity.
weight of various media is also considered for overload throttling. For
example, video takes significantly more capacity than audio.
However, these are
overload-protection methods only; they are not intended to enforce licensed or
rated capacity. They reflect the levels at which the product has been tested,
and they exist so that MediaSense nodes can protect themselves and offer
graceful service degradation in case of severe overuse.
It is still the customer's responsibility to engineer his or her
deployment such that the overall rated node and cluster capacities are not
protects itself with respect to media storage capacity. It raises alarms,
redirects new calls to other nodes (if available), prunes older recordings to
recover space (if permitted), and even drops existing calls (as a last resort)
in order to maintain the integrity of existing recordings.
The Real Time
Monitoring Tool (RTMT) provides a great deal of statistical information about
use levels and throttling activities for each node.