Provided by: trafficserver_9.1.3+ds-1_amd64 
NAME
traffic_top - Display Traffic Server statistics
DESCRIPTION
The traffic_top program provides a simple CLI view of your Traffic Server statistics,
reminiscent of programs like top(1) and nmon(1) for system processes and statistics.
OPTIONS
-s COUNT
Number of seconds in between each polling of the Traffic Server statistics API. The
default is 5 seconds.
URL|hostname|hostname:port
Location at which the JSON output of Traffic Server statistics are accessible.
REQUIREMENTS
The traffic_top program requires that your Traffic Server nodes are running the Stats Over
HTTP plugin and that the machine from which you run traffic_top is able to access the
HTTP(S) end point for the plugin.
If, for example, you have the following entry in your plugin.config to enable the plugin:
stats_over_http.so statistics
And your Traffic Server node is accessible using the hostname ats.example.tld (listening
on port 80), then you would run traffic_top as follows:
traffic_top http://ats.example.tld/statistics
The hostname, port, and path to the Stats Over HTTP plugin JSON output should be adjusted
as necessary to match your environment.
IMPORTANT:
The statistics provided by Traffic Server (through traffic_ctl and Stats Over HTTP
Plugin) expose quite a bit about the inner workings of your Traffic Server cache. While
consumers of the JSON statistics endpoint won't be able to see or modify the raw
contents of your cache, it is still very strongly advised to limit access to this URL.
INTERFACE
Upon startup (and successful connection to the Stats Over HTTP Plugin endpoint), you will
be presented with a curses interface that looks like:
[image: Main interface for the traffic_top command line program.] [image] Main
interface for the traffic_top command line program..UNINDENT
Each area of the main interface is explained in the following sections.
Cache Information
Disk Used
The amount of disk space currently in use by the Traffic Server cache. This number will
never exceed Disk Total.
Statistic: proxy.process.cache.bytes_used.
Disk Total
Total disk space allocated for Traffic Server cache.
Statistic: proxy.process.cache.bytes_total.
Ram Used
Current amount of RAM Cache occupied by objects. Objects located and served from the
Traffic Server RAM Cache avoid the much slower disk I/O necessary to serve from spinning
rust.
Statistic: proxy.process.cache.ram_cache.bytes_used
Ram Total
Total space allocated for used by the Traffic Server RAM Cache.
Statistic: proxy.process.cache.ram_cache.total_bytes
Lookups
Total cache object lookups performed, including disk and RAM caches.
Statistic: proxy.process.http.cache_lookups
Writes
Total number of object writes to the Traffic Server cache.
Statistic: proxy.process.http.cache_writes.
Updates
Total number of existing cache objects which have been updated with new content from the
origin server (i.e. existing cache object was stale, so Traffic Server revalidated against
the origin and received a new object).
Statistic: proxy.process.http.cache_updates.
Deletes
Total number of Traffic Server cache objects which have been deleted (generally through a
PURGE request).
Statistic: proxy.process.http.cache_deletes.
Read Active
Current number of active cache reads.
Statistic: proxy.process.cache.read.active.
Writes Act
Current number of active cache writes.
Statistic: proxy.process.cache.write.active.
Update Act
Current number of active cache updates.
Statistic: proxy.process.cache.update.active.
Entries
The current number of cache directory entries in use.
Statistic: proxy.process.cache.direntries.used.
Avg Size
The average size of current in the cache directory. This is calculated by dividing Entries
into Disk Used.
Statistics: proxy.process.cache.bytes_used, proxy.process.cache.direntries.used.
DNS Lookup
Total number of DNS lookups performed by Traffic Server, regardless of whether they were
full DNS queries or were satisfied by entries in the HostDB cache. If you are not
operating a forward proxy and if none of your origin servers are mapped by hostnames, then
it is normal for your HostDB cache to be empty.
Statistic: proxy.process.hostdb.total_lookups.
DNS Hits
Total number of DNS lookups which were successfully served from the HostDB cache.
Statistic: proxy.process.hostdb.total_hits.
Ram Hit
The percentage of cache lookups which were served successfully from the RAM Cache (thus
avoiding slower I/O from the disk cache, or even slower network I/O to the origin server).
This is calculated as a ratio from the two RAM Cache statistics for hits and misses.
Statistics: proxy.process.cache.ram_cache.hits, proxy.process.cache.ram_cache.misses.
Fresh
The percentage of cache lookups which located a fresh cache object (i.e. an object not in
need of any revalidation). These transactions are served directly from the cache to the
client without any need to contact origin servers or spend time updating the cache. An
effective Traffic Server cache will have a very high Fresh percentage, as these are the
fastest responses to clients.
Statistic: proxy.process.http.transaction_counts.hit_fresh.
Revalidate
The percentage of cache lookups which located a stale cache object, but for which the
origin server did not return new data when Traffic Server revalidated the object.
Revalidated objects don't incur cache update performance hits, but they do still lead to
(what ends up being unnecessary) network traffic with origin servers.
A high percentage of revalidated cache lookups may indicate that Traffic Server is being
too aggressive with its object staleness heuristics.
Statistic: proxy.process.http.transaction_counts.hit_revalidated.
Cold
The percentage of cache lookups which located an expired cache object. These were requests
which located a matching object in the cache, but it had already been expired fully and a
new copy was retrieved from the origin server. Unfortunately, the new copy from the
origin server ended up being the unchanged from what had been marked expired in the cache.
A high percentage of cold misses indicates that your origin servers are setting
expirations on their responses which are too short, as compared to the actual lifetime of
the content in those responses.
Statistic: proxy.process.http.transaction_counts.miss_cold.
Changed
The percentage of cache lookups which located an expired cache object and which resulted
in new data being retrieved from the origin server.
Statistic: proxy.process.http.transaction_counts.miss_changed.
Not Cache
The percentage of requests for which the requested object was marked not cacheable by the
origin server. A high percentage of uncacheable objects may indicate that either your
origin servers simply contain a large amount of dynamic, uncacheable data, or that they
are not properly setting cache control headers in their responses.
Statistic: proxy.process.http.transaction_counts.miss_not_cacheable.
No Cache
The percentage of requests for which the client indicated that the cache should not be
used (e.g. a Cache-Control: no-cache request header was present).
A high percentage of these requests may indicate possible client-side abuse of your proxy,
in which a disproportionate number of client connections are attempting to force their way
past your Traffic Server cache.
Statistic: proxy.process.http.transaction_counts.miss_client_no_cache.
Fresh (ms)
The average amount of time per lookup (in milliseconds) spent serving requests which were
served by fresh cache lookups. Note that the underlying statistic is the total amount of
time Traffic Server has spent serving these requests since startup, whereas traffic_top is
displaying the number averaged by the total Fresh requests.
Statistic: proxy.process.http.transaction_totaltime.hit_fresh.
Reval (ms)
The average amount of time per lookup (in milliseconds) spent serving requests which
involved revalidating a stale object for which the origin server did not return new data.
Note that the underlying statistic is the total amount of time Traffic Server has spent
serving these requests since startup, whereas traffic_top is displaying the number
averaged by the total Revalidate requests.
Statistic: proxy.process.http.transaction_totaltime.hit_revalidated.
Cold (ms)
The average amount of time per lookup (in milliseconds) spent serving requests which
involved expired cache objects. Note that the underlying statistic is the total amount of
time Traffic Server has spent serving these requests since startup, whereas traffic_top is
displaying the number averaged by the total Cold requests.
Statistic: proxy.process.http.transaction_totaltime.miss_cold.
Chang (ms)
The average amount of time per lookup (in milliseconds) spent serving requests which were
served by Traffic Server with new data obtained from an origin server. Note that the
underlying statistic is the total amount of time Traffic Server has spent serving these
requests since startup, whereas traffic_top is displaying the number averaged by the total
Changed requests.
Statistic: proxy.process.http.transaction_totaltime.miss_changed.
Not (ms)
The average amount of time per lookup (in milliseconds) spent serving requests which were
served from the origin server because it had marked the object as uncacheable. Note that
the underlying statistic is the total amount of time Traffic Server has spent serving
these requests since startup, whereas traffic_top is displaying the number averaged by the
total Not Cache requests.
Statistic: proxy.process.http.transaction_totaltime.miss_not_cacheable.
No (ms)
The average amount of time per lookup (in milliseconds) spent serving requests which were
served by the origin server because the client had requested that the Traffic Server cache
be bypassed. Note that the underlying statistic is the total amount of time Traffic Server
has spent serving these requests since startup, whereas traffic_top is displaying the
number averaged by the total No Cache requests.
Statistic: proxy.process.http.transaction_totaltime.miss_client_no_cache.
DNS Hit
The percentage of DNS lookups which were served from the HostDB cache, rather than
requiring full DNS queries.
Statistics: proxy.process.hostdb.total_hits, proxy.process.hostdb.total_lookups.
DNS Entry
The total number of entries in the HostDB lookup cache. If you are not operating a forward
proxy and if none of your origin servers are mapped by hostnames, then it is normal for
your HostDB cache to be empty.
Statistic: proxy.process.hostdb.cache.current_items.
Client Request & Response
GET, HEAD, POST
Each of these display the percentage of total requests by clients to Traffic Server which
used the given HTTP method.
Statistics: proxy.process.http.get_requests, proxy.process.http.head_requests,
proxy.process.http.post_requests.
2xx
Percentage of all requests made to Traffic Server which resulted in an HTTP response code
between 200 and 299 (inclusive) being sent back to the client. 2xx response codes all
indicate some form of successful transaction with content delivered.
Statistic: proxy.process.http.2xx_responses.
3xx
Percentage of all requests made to Traffic Server which resulted in an HTTP response code
between 300 and 399 (inclusive) being sent back to the client. 3xx response codes indicate
non-error conditions; most commonly redirects or IMS not-modified responses that did not
deliver content (because they did not need to).
Statistic: proxy.process.http.3xx_responses.
4xx
Percentage of all requests made to Traffic Server which resulted in an HTTP response code
between 400 and 499 (inclusive) being sent back to the client. 4xx response codes are used
for requests which included a client-side error. Most frequently these responses are for
invalid URLs (e.g. 404 Not Found), but also include authentication failures (e.g. 403
Forbidden). In short, Traffic Server refused to fulfill the request because the client
sent invalid or incorrect information.
Statistic: proxy.process.http.4xx_responses.
5xx
Percentage of all requests made to Traffic Server which resulted in an HTTP response code
between 500 and 599 (inclusive) being sent back to the client. 5xx response code indicate
a server-side error. For a caching proxy like Traffic Server, these are likely to be most
often returned for gateway errors; e.g. 502 Bad Gateway (the origin server address was
invalid or a connection could not be established at all due to system or network failures)
and 504 Gateway Timeout (the origin server was contacted, but did not return data in the
time allowed).
Statistic: proxy.process.http.5xx_responses.
Conn Fail
The total number of connections to Traffic Server which failed to connect properly.
Statistic: proxy.process.http.transaction_counts.errors.connect_failed.
Other Err
The total number of Traffic Server transactions which experienced an error not covered by
Conn Fail and Abort.
Statistic: proxy.process.http.transaction_counts.errors.other.
Abort
The total number of Traffic Server transactions which were prematurely ended (connection
was closed before all data had been received and/or sent).
Statistic: proxy.process.http.transaction_counts.errors.aborts.
200, 206, 301, 302, 304, 404, 502
The percentage of total Traffic Server transactions which resulted in the specified HTTP
response code. For details on the meaning of individual status codes, please refer to HTTP
Status Codes.
Statistics: proxy.process.http.200_responses, proxy.process.http.206_responses,
proxy.process.http.301_responses, proxy.process.http.302_responses,
proxy.process.http.304_responses, proxy.process.http.404_responses,
proxy.process.http.502_responses.
NOTE:
Traffic Server also provides statistics for every other response code. The keen
observer will have hopefully already recognized the pattern in statistic names.
100 B, 1 KB, 3 KB, 5 KB, 10 KB, 1 MB, > 1 MB
Each of these fields indicates the percentage of responses from Traffic Server which fell
within a particular size (document body size, excluding response headers). The individual
fields are the upper bounds of exclusive buckets, meaning that a response with a document
body of 4,500 bytes will be counted in the 5 KB field, but not in any of the smaller
sizes.
Statistics: proxy.process.http.response_document_size_100,
proxy.process.http.response_document_size_1K,
proxy.process.http.response_document_size_3K,
proxy.process.http.response_document_size_5K,
proxy.process.http.response_document_size_10K,
proxy.process.http.response_document_size_1M,
proxy.process.http.response_document_size_inf.
Client
Requests
Total number of client requests serviced by Traffic Server. This includes both successful
content-bearing responses as well as errors, redirects, and not-modified IMS responses.
Additionally, this number includes requests which were serviced from the Traffic Server
cache as well as through proxied origin connections.
Statistic: proxy.process.http.incoming_requests.
Req/Conn
The average number of requests made per client connection. When Keep-Alive support is
enabled in Traffic Server and clients make use of it, they are able to submit multiple
document requests over a single connection in some situations. This number is calculated
from the total number of client requests divided by the total number of new connections
that have been created.
Statistics: proxy.process.http.incoming_requests,
proxy.process.http.total_client_connections.
New Conn
The total number of new HTTP connections from clients which have been created over the
lifetime of the Traffic Server process.
Statistic: proxy.process.http.total_client_connections.
Curr Conn
The number of currently-open HTTP connections from clients with Traffic Server.
Statistic: proxy.process.http.current_client_connections.
Active Con
The number of currently active client connection threads (requests in the process of being
fulfilled when the statistics snapshot was taken).
Statistic: proxy.process.http.current_active_client_connections.
Dynamic KA
Statistics: proxy.process.net.dynamic_keep_alive_timeout_in_total,
proxy.process.net.dynamic_keep_alive_timeout_in_count.
Head Bytes
The total bytes consumed by outgoing server response headers from Traffic Server to
clients.
Statistic: proxy.process.http.user_agent_response_header_total_size.
Body Bytes
The total bytes consumed by outgoing document bodies in responses from Traffic Server to
clients.
Statistic: proxy.process.http.user_agent_response_document_total_size.
Avg Size
Average size in bytes of combined headers and document bodies for Traffic Server responses
to clients.
Statistics: proxy.process.http.user_agent_response_header_total_size,
proxy.process.http.user_agent_response_document_total_size,
proxy.process.http.incoming_requests.
Net (bits)
The summed bits (not bytes) of all Traffic Server responses to clients, whether served
from the Traffic Server or through a proxied connection to an origin server.
Statistics: proxy.process.http.user_agent_response_header_total_size,
proxy.process.http.user_agent_response_document_total_size.
Resp (ms)
The average response time by Traffic Server across all client requests. Response time is
measured from the moment a client connection is established, until the moment the last
byte of the response is delivered. This field is simply the result of dividing the total
time spent by Traffic Server servicing client requests by the total number of those
requests.
Statistics: proxy.process.http.total_transactions_time,
proxy.process.http.incoming_requests.
Origin Server
Requests
The total number of requests made by Traffic Server to origin servers, because client
requests could not be fulfilled by the Traffic Server cache (for any reason, whether it
was not present in the cache, was stale or expired, or not cacheable).
Statistic: proxy.process.http.outgoing_requests.
Req/Conn
The average number of requests made to origin servers by Traffic Server per connection.
This field is simply the result of dividing the total number of requests made by the total
number of connections that have ever been opened.
Statistics: proxy.process.http.outgoing_requests,
proxy.process.http.total_server_connections.
New Conn
The total number of new HTTP connections from Traffic Server to origin servers that have
been created during the lifetime of the Traffic Server process.
Statistic: proxy.process.http.total_server_connections.
Curr Conn
The number of HTTP connections currently open from Traffic Server to origin servers. Note
that Traffic Server maintains a configurable number of origin server connections open at
all times, whether there are requests being proxied or not, when configured as a reverse
proxy to a known list of origin servers. This is not the case for forward proxy
configurations, however, as Traffic Server has no foreknowledge of the servers to which
clients may try to connect.
Statistic: proxy.process.http.current_server_connections.
Head Bytes
The total bytes delivered as headers in responses from origin servers to Traffic Server.
Statistic: proxy.process.http.origin_server_response_header_total_size.
Body Bytes
The total bytes delivered as document bodies in responses from origin servers to Traffic
Server.
Statistic: proxy.process.http.origin_server_response_document_total_size.
Avg Size
The average size of the combined header and document body responses from origin servers to
Traffic Server.
Statistics: proxy.process.http.origin_server_response_header_total_size,
proxy.process.http.origin_server_response_document_total_size,
proxy.process.http.outgoing_requests.
Net (bits)
The total bits (not bytes) transferred from origin servers to Traffic Server for proxied
requests not fulfilled by the Traffic Server cache.
Statistics: proxy.process.http.origin_server_response_header_total_size,
proxy.process.http.origin_server_response_document_total_size.
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