When using hash-based load balancing, requests are always assigned to
the server corresponding to the hash bucket for the balancing key,
without taking maxconn or maxqueue into account, unlike in other load
balancing methods like 'first'. This adds a new backend directive that
can be used to take maxconn and possibly maxqueue in that context. This
can be used when hashing is desired to achieve cache locality, but
sending requests to a different server is preferable to queuing for a
long time or failing requests when the initial server is saturated.
By default, affinity is preserved as was the case previously. When
'hash-preserve-affinity' is set to 'maxqueue', servers are considered
successively in the order of the hash ring until a server that does not
have a full queue is found.
When 'maxconn' is set on a server, queueing cannot be disabled, as
'maxqueue=0' means unlimited. To support picking a different server
when a server is at 'maxconn' irrespective of the queue,
'hash-preserve-affinity' can be set to 'maxconn'.
It's been warning as being deprecated since 2.0-dev4, it's about time
to drop it now. The error message recommends to either remove it or
use "option httpclose" instead. It's still referred to in the old
internal doc about the connection header, which itself seems highly
inaccurate by now.
These are a collection of test files for a variety of features (old or
more recent). 2 or 3 files were found lying there non-committed and
were moved at the same time. A few deprecated or obsolete keywords were
updated to their recent equivalent. Many of these configurations are
made to trigger different parsing errors so it is normal that plenty
of them fail.
Now the tests directory is cleaner and easier to navigate through.
