..
	Copyright (c) 2017-2021 Varnish Software AS
	SPDX-License-Identifier: BSD-2-Clause
	See LICENSE file for full text of license

..
	This is *NOT* a RST file but the syntax has been chosen so
	that it may become an RST file at some later date.

.. vinyl_vsc_begin::	vbe
	:oneliner:	Backend Counters
	:order:		60

.. vinyl_vsc:: happy
	:type:	bitmap
	:format:	bitmap
	:level:	info
	:oneliner:	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.

.. vinyl_vsc:: bereq_hdrbytes
	:type:	counter
	:level:	info
	:format: bytes
	:oneliner:	Request header bytes

	Total backend request header bytes sent

.. vinyl_vsc:: bereq_bodybytes
	:type:	counter
	:level:	info
	:format: bytes
	:oneliner:	Request body bytes

	Total backend request body bytes sent

.. vinyl_vsc:: beresp_hdrbytes
	:type:	counter
	:level:	info
	:format: bytes
	:oneliner:	Response header bytes

	Total backend response header bytes received

.. vinyl_vsc:: beresp_bodybytes
	:type:	counter
	:level:	info
	:format: bytes
	:oneliner:	Response body bytes

	Total backend response body bytes received

.. vinyl_vsc:: pipe_hdrbytes
	:type:	counter
	:level:	info
	:format: bytes
	:oneliner:	Pipe request header bytes

	Total request bytes sent for piped sessions

.. vinyl_vsc:: pipe_out
	:type:	counter
	:level:	info
	:format: bytes
	:oneliner:	Piped bytes to backend

	Total number of bytes forwarded to backend in pipe sessions

.. vinyl_vsc:: pipe_in
	:type:	counter
	:level:	info
	:format: bytes
	:oneliner:	Piped bytes from backend

	Total number of bytes forwarded from backend in pipe sessions

.. vinyl_vsc:: conn
	:type:	gauge
	:level:	info
	:oneliner:	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.

.. vinyl_vsc:: req
	:type:	counter
	:level:	info
	:oneliner:	Backend requests sent

.. vinyl_vsc:: unhealthy
	:type:	counter
	:level: info
	:oneliner:	Fetches not attempted due to backend being unhealthy

.. vinyl_vsc:: busy
	:type:	counter
	:level: info
	:oneliner:	Fetches not attempted due to backend being busy

	Number of times the max_connections limit was reached

..
	=== Anything below is actually per VCP entry, but collected per
	=== backend for simplicity

.. vinyl_vsc:: fail
	:type:	counter
	:level: info
	:oneliner:	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.

.. vinyl_vsc:: fail_eacces
	:type:	counter
	:level: diag
	:oneliner:	Connections failed with EACCES or EPERM

.. vinyl_vsc:: fail_eaddrnotavail
	:type:	counter
	:level: diag
	:oneliner:	Connections failed with EADDRNOTAVAIL

.. vinyl_vsc:: fail_econnrefused
	:type:	counter
	:level: diag
	:oneliner:	Connections failed with ECONNREFUSED

.. vinyl_vsc:: fail_enetunreach
	:type:	counter
	:level: diag
	:oneliner:	Connections failed with ENETUNREACH

.. vinyl_vsc:: fail_etimedout
	:type:	counter
	:level: diag
	:oneliner:	Connections failed ETIMEDOUT

.. vinyl_vsc:: fail_other
	:type:	counter
	:level: diag
	:oneliner:	Connections failed for other reason

.. vinyl_vsc:: helddown
	:type:	counter
	:level: diag
	:oneliner:	Connection opens not attempted

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

.. vinyl_vsc_end::	vbe
