Provided by: trafficserver_7.1.2+ds-3_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 admin-plugins-stats-over-http)
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 admin-plugins-stats-over-http 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 Activ
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 appendix-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.
COPYRIGHT
2018, dev@trafficserver.apache.org
7.1 Feb 16, 2018 TRAFFIC_TOP(1)