Counters which track the activity in the different classes of mutex-locks.

The counts may be slightly wrong if there are more than one lock instantiated in each class (ie: .creat > 1)

Created locks

Destroyed locks

Lock Operations

Contended lock operations

If the lck debug bit is set: Lock operations which returned EBUSY on the first locking attempt.

If the lck debug bit is unset, this counter will never be incremented even if lock operations are contended.

Contended trylock operations

If the lck debug bit is set: Trylock operations which returned EBUSY.

If the lck debug bit is unset, this counter will never be incremented even if lock operations are contended.

stat summ operations

Number of times per-thread statistics were summed into the global counters.

Child process uptime

How long the child process has been running.

Sessions accepted

Count of sessions successfully accepted

Session accept failures

Count of failures to accept TCP connection.

This counter is the sum of the sess_fail_* counters, which give more detailed information.

Session accept failures: connection aborted

Detailed reason for sess_fail: Connection aborted by the client, usually harmless.

Session accept failures: interrupted system call

Detailed reason for sess_fail: The accept() call was interrupted, usually harmless

Session accept failures: too many open files

Detailed reason for sess_fail: No file descriptor was available. Consider raising RLIMIT_NOFILE (see ulimit -n).

Session accept failures: bad file descriptor

Detailed reason for sess_fail: The listen socket file descriptor was invalid. Should never happen.

Session accept failures: not enough memory

Detailed reason for sess_fail: Most likely insufficient socket buffer memory. Should never happen

Session accept failures: other

Detailed reason for sess_fail: neither of the above, see SessError log (varnishlog -g raw -i SessError).

Client requests received, subject to 400 errors

400 means we couldn't make sense of the request, it was malformed in some drastic way.

Client requests received, subject to 417 errors

417 means that something went wrong with an Expect: header.

Good client requests received

The count of parseable client requests seen.

ESI subrequests

Number of ESI subrequests made.

Cache hits

Count of cache hits. A cache hit indicates that an object has been delivered to a client without fetching it from a backend server.

Cache grace hits

Count of cache hits with grace. A cache hit with grace is a cache hit where the object is expired. Note that such hits are also included in the cache_hit counter.

Cache hits for pass.

Count of hits for pass. A cache hit for pass indicates that Varnish is going to pass the request to the backend and this decision has been cached in it self. This counts how many times the cached decision is being used.

Cache hits for miss.

Count of hits for miss. A cache hit for miss indicates that Varnish is going to proceed as for a cache miss without request coalescing, and this decision has been cached. This counts how many times the cached decision is being used.

Cache misses

Count of misses. A cache miss indicates the object was fetched from the backend before delivering it to the client.

Count of backend responses considered uncacheable.

Count of objects created with ttl+grace+keep shorter than the 'shortlived' runtime parameter.

Backend conn. success

How many backend connections have successfully been established.

Backend conn. not attempted

Backend conn. too many

Backend conn. failures

Backend conn. reuses

Count of backend connection reuses. This counter is increased whenever we reuse a recycled connection.

Backend conn. recycles

Count of backend connection recycles. This counter is increased whenever we have a keep-alive connection that is put back into the pool of connections. It has not yet been used, but it might be, unless the backend closes it.

Backend conn. retry

Backend conn. waited in queue for a connection

Count of backend requests that waited in a backend_wait queue for a connection to become available. The size of a backend wait queue is defined by the backend wait_limit property. The wait queue is only used when max_connections to the backend are in use.

Backend conn. waited in queue and did not get a connection

Count of backend requests that waited in a backend_wait queue for a connection to become available and did not get one (timed out). The maximum time to wait in the queue is defined by the backend wait_timeout property.

Fetch no body (HEAD)

beresp with no body because the request is HEAD.

Fetch with Length

beresp.body with Content-Length.

Fetch chunked

beresp.body with Chunked.

Fetch EOF

beresp.body with EOF.

Fetch bad T-E

beresp.body length/fetch could not be determined.

Fetch no body

beresp.body empty

Fetch no body (1xx)

beresp with no body because of 1XX response.

Fetch no body (204)

beresp with no body because of 204 response.

Fetch no body (304)

beresp with no body because of 304 response.

Fetch failed (all causes)

beresp fetch failed.

Background fetch failed (no thread)

A bgfetch triggered by a grace hit failed, no thread available.

Number of thread pools

Number of thread pools. See also parameter thread_pools. NB: Presently pools cannot be removed once created.

Total number of threads

Number of threads in all pools. See also parameters thread_pools, thread_pool_min and thread_pool_max.

Threads hit max

Number of times more threads were needed, but limit was reached in a thread pool. See also parameter thread_pool_max.

Threads created

Total number of threads created in all pools.

Threads destroyed

Total number of threads destroyed in all pools.

Thread creation failed

Number of times creating a thread failed. See VSL::Debug for diagnostics. See also parameter thread_fail_delay.

Length of session queue

Length of session queue waiting for threads. NB: Only updates once per second. See also parameter thread_queue_limit.

Number of requests sent to sleep on busy objhdr

Number of requests sent to sleep without a worker thread because they found a busy object.

Number of requests woken after sleep on busy objhdr

Number of requests taken off the busy object sleep list and rescheduled.

Number of requests killed after sleep on busy objhdr

Number of requests killed from the busy object sleep list due to lack of resources.

Sessions queued for thread

Number of times session was queued waiting for a thread. See also parameter thread_queue_limit.

Sessions dropped for thread

Number of times an HTTP/1 session was dropped because the queue was too long already. See also parameter thread_queue_limit.

Requests dropped

Number of times an HTTP/2 stream was refused because the queue was too long already. See also parameter thread_queue_limit.

Requests reset

Number of times a client left before the VCL processing of its requests completed. For HTTP/2 sessions, either the stream was reset by an RST_STREAM frame from the client, or a stream or connection error occurred.

object structs made

Approximate number of HTTP objects (headers + body, if present) in the cache.

unresurrected objects

Number of unresurrected objects

objectcore structs made

Approximate number of object metadata elements in the cache. Each object needs an objectcore, extra objectcores are for hit-for-miss, hit-for-pass and busy objects.

objecthead structs made

Approximate number of different hash entries in the cache.

Number of backends

Number of backends known to us.

Number of expired objects

Number of objects that expired from cache because of old age.

Number of superseded objects

Number of times an object was superseded by a new one.

Number of LRU nuked objects

How many objects have been forcefully evicted from storage to make room for a new object.

Number of LRU moved objects

Number of move operations done on the LRU list.

Reached nuke_limit

Number of times more storage space were needed, but limit was reached in a nuke_limit. See also parameter nuke_limit.

HTTP header overflows

Total sessions seen

Number of ongoing pipe sessions

Pipes hit pipe_sess_max

Number of times more pipes were needed, but the limit was reached. See also parameter pipe_sess_max.

Total pipe sessions seen

Total pass-ed requests seen

Total backend fetches initiated

Total backend fetches initiated, including background fetches.

Total backend background fetches initiated

Total synthetic responses made

Request header bytes

Total request header bytes received

Request body bytes

Total request body bytes received

Response header bytes

Total response header bytes transmitted

Response body bytes

Total response body bytes transmitted

Pipe request header bytes

Total request bytes received for piped sessions

Piped bytes from client

Total number of bytes forwarded from clients in pipe sessions

Piped bytes to client

Total number of bytes forwarded to clients in pipe sessions

Session Closed

Session Closed with error

Total number of sessions closed with errors. See sc_* diag counters for detailed breakdown

Session Read Ahead

Session herd

Number of times the timeout_linger triggered

Session OK REM_CLOSE

Number of session closes with REM_CLOSE (Client Closed)

Session OK REQ_CLOSE

Number of session closes with REQ_CLOSE (Client requested close)

Session Err REQ_HTTP10

Number of session closes with Error REQ_HTTP10 (Proto < HTTP/1.1)

Session Err RX_BAD

Number of session closes with Error RX_BAD (Received bad req/resp)

Session Err RX_BODY

Number of session closes with Error RX_BODY (Failure receiving req.body)

Session Err RX_JUNK

Number of session closes with Error RX_JUNK (Received junk data)

Session Err RX_OVERFLOW

Number of session closes with Error RX_OVERFLOW (Received buffer overflow)

Session Err RX_TIMEOUT

Number of session closes with Error RX_TIMEOUT (Receive timeout)

Session Err RX_CLOSE_IDLE

Number of session closes with Error RX_CLOSE_IDLE: timeout_idle has been exceeded while waiting for a client request.

Session OK TX_PIPE

Number of session closes with TX_PIPE (Piped transaction)

Session Err TX_ERROR

Number of session closes with Error TX_ERROR (Error transaction)

Session OK TX_EOF

Number of session closes with TX_EOF (EOF transmission)

Session OK RESP_CLOSE

Number of session closes with RESP_CLOSE (Backend/VCL requested close)

Session Err OVERLOAD

Number of session closes with Error OVERLOAD (Out of some resource)

Session Err PIPE_OVERFLOW

Number of session closes with Error PIPE_OVERFLOW (Session pipe overflow)

Session Err RANGE_SHORT

Number of session closes with Error RANGE_SHORT (Insufficient data for range)

Session Err REQ_HTTP20

Number of session closes with Error REQ_HTTP20 (HTTP2 not accepted)

Session Err VCL_FAILURE

Number of session closes with Error VCL_FAILURE (VCL failure)

Number of times we failed an http/2 session because it hit its configured limits for the number of permitted rapid stream resets.

Session Err BANKRUPT

Number of times we failed an http/2 session because all the streams were waiting for their windows to be credited when h2_window_timeout triggered.

Delivery failed due to insufficient workspace.

Number of times we failed a response due to running out of workspace memory during delivery.

workspace_backend overflows

Number of times we ran out of space in workspace_backend.

workspace_client overflows

Number of times we ran out of space in workspace_client.

workspace_thread overflows

Number of times we ran out of space in workspace_thread.

workspace_session overflows

Number of times we ran out of space in workspace_session.

SHM records

Number of log records written to the shared memory log.

SHM writes

Number of individual writes to the shared memory log. A single write may batch multiple records for buffered tasks.

SHM flushes due to overflow

Number of writes performed before the end of a buffered task because adding a record to a batch would exceed vsl_buffer.

SHM lock contention

Number of times a write had to wait for the lock.

SHM cycles through VSL space

Number of times a write of log records would reach past the end of the shared memory log, cycling back to the beginning.

SHM bytes

Number of bytes written to the shared memory log.

Backend requests made

Number of loaded VCLs in total

Number of VCLs available

Number of discarded VCLs

VCL failures

Count of failures which prevented VCL from completing.

Count of bans

Number of all bans in system, including bans superseded by newer bans and bans already checked by the ban-lurker.

Number of bans marked 'completed'

Number of bans which are no longer active, either because they got checked by the ban-lurker or superseded by newer identical bans.

Number of bans using obj.*

Number of bans which use obj.* variables. These bans can possibly be washed by the ban-lurker.

Number of bans using req.*

Number of bans which use req.* variables. These bans cannot be washed by the ban-lurker.

Bans added

Counter of bans added to ban list.

Bans deleted

Counter of bans deleted from ban list.

Bans tested against objects (lookup)

Count of how many bans and objects have been tested against each other during hash lookup.

Objects killed by bans (lookup)

Number of objects killed by bans during object lookup.

Bans tested against objects (lurker)

Count of how many bans and objects have been tested against each other by the ban-lurker.

Ban tests tested against objects (lookup)

Count of how many tests and objects have been tested against each other during lookup. 'ban req.url == foo && req.http.host == bar' counts as one in 'bans_tested' and as two in 'bans_tests_tested'

Ban tests tested against objects (lurker)

Count of how many tests and objects have been tested against each other by the ban-lurker. 'ban req.url == foo && req.http.host == bar' counts as one in 'bans_tested' and as two in 'bans_tests_tested'

Objects killed by bans (lurker)

Number of objects killed by the ban-lurker.

Objects killed by bans for cutoff (lurker)

Number of objects killed by the ban-lurker to keep the number of bans below ban_cutoff.

Bans superseded by other bans

Count of bans replaced by later identical bans.

Lurker gave way for lookup

Number of times the ban-lurker had to wait for lookups.

Bytes used by the persisted ban lists

Number of bytes used by the persisted ban lists.

Extra bytes in persisted ban lists due to fragmentation

Number of extra bytes accumulated through dropped and completed bans in the persistent ban lists.

Number of purge operations executed

Number of purged objects

Number of objects mailed to expiry thread

Number of objects mailed to expiry thread for handling.

Number of objects received by expiry thread

Number of objects received by expiry thread for handling.

HCB Lookups without lock

HCB Lookups with lock

HCB Inserts

ESI parse errors (unlock)

ESI parse warnings (unlock)

Loaded VMODs

Gzip operations

Gunzip operations

Test gunzip operations

Those operations occur when Varnish receives a compressed object from a backend. They are done to verify the gzip stream while it's inserted in storage.

Premature iovec flushes

Number of additional writes performed on HTTP1 connections because the number of IO vectors was too small to submit all possible IO in one go. This number is configured through the http1_iovs parameter for client connections and implicitly defined by the amount of free workspace for backend connections.

In use

In Pool

Size requested

Size allocated

Allocations

Frees

Recycled from pool

Timed out from pool

Too small to recycle

Too many for pool

Pool ran dry

Management process uptime

Uptime in seconds of the management process

Child process started

Number of times the child process has been started

Child process normal exit

Number of times the child process has been cleanly stopped

Child process unexpected exit

Number of times the child process has exited with an unexpected return code

Child process died (signal)

Number of times the child process has died due to signals

Child process core dumped

Number of times the child process has produced core dumps

Child process panic

Number of times the management process has caught a child panic

Allocator requests

Number of times the storage has been asked to provide a storage segment.

Allocator failures

Number of times the storage has failed to provide a storage segment.

Bytes allocated

Number of total bytes allocated by this storage.

Bytes freed

Number of total bytes returned to this storage.

Allocations outstanding

Number of storage allocations outstanding.

Bytes outstanding

Number of bytes allocated from the storage.

Bytes available

Number of bytes left in the storage.

Allocator requests

Number of times the storage has been asked to provide a storage segment.

Allocator failures

Number of times the storage has failed to provide a storage segment.

Bytes allocated

Number of total bytes allocated by this storage.

Bytes freed

Number of total bytes returned to this storage.

Allocations outstanding

Number of storage allocations outstanding.

Bytes outstanding

Number of bytes allocated from the storage.

Bytes available

Number of bytes left in the storage.

N struct smf

N small free smf

N large free smf

Allocator requests

Number of times the storage has been asked to provide a storage segment.

Allocator failures

Number of times the storage has failed to provide a storage segment.

Bytes allocated

Number of total bytes allocated by this storage.

Bytes freed

Number of total bytes returned to this storage.

Allocations outstanding

Number of storage allocations outstanding.

Bytes outstanding

Number of bytes allocated from the storage.

Bytes available

Number of bytes left in the storage.

Happy health probes

Represents the last probe results as a bitmap. Happy probes are bits set to 1, and the unhappy ones are set to 0. The highest bits represent the oldest probes.

Request header bytes

Total backend request header bytes sent

Request body bytes

Total backend request body bytes sent

Response header bytes

Total backend response header bytes received

Response body bytes

Total backend response body bytes received

Pipe request header bytes

Total request bytes sent for piped sessions

Piped bytes to backend

Total number of bytes forwarded to backend in pipe sessions

Piped bytes from backend

Total number of bytes forwarded from backend in pipe sessions

Concurrent connections used

The number of currently used connections to the backend. This number is always less or equal to the number of connections to the backend (as, for example shown as ESTABLISHED for TCP connections in netstat) due to connection pooling.

Backend requests sent

Fetches not attempted due to backend being unhealthy

Fetches not attempted due to backend being busy

Number of times the max_connections limit was reached

Connections failed

Counter of failed opens. Detailed reasons are given in the fail_* counters (DIAG level) and in the log under the FetchError tag.

This counter is the sum of all detailed fail_* counters.

All fail_* counters may be slightly inaccurate for efficiency.

Connections failed with EACCES or EPERM

Connections failed with EADDRNOTAVAIL

Connections failed with ECONNREFUSED

Connections failed with ENETUNREACH

Connections failed ETIMEDOUT

Connections failed for other reason

Connection opens not attempted

Connections not attempted during the backend_local_error_holddown or backend_remote_error_holddown interval after a fundamental connection issue.

Number of idle connections

Number of idle connections being waited over.

Number of idle connections closed by peer

Number of idle connections that experienced closure by peer while being waited for.

Number of idle connections timeout

Number of idle connections that experienced a timeout event while being waited for.

Number of idle connections read events

Number of idle connections that experienced a read event while being waited for.