Upgrading to Varnish 6.4.0¶
Upgrading to Varnish 6.4 from 6.3 should not require any changes to VCL.
This document contains information about other relevant aspects which should be considered when upgrading.
varnishd¶
The hash algorithm of the
hash
director was changed, so backend selection will change once only when upgrading.Users of the
hash
director are advised to consider using theshard
director instead, which, amongst other advantages, offers more stable backend selection through consistent hashing.We fixed a case where
send_timeout
had no effect when streaming from a backend fetch.Users with long running backend fetches should watch out of increases connection close rates and consider increasing
send_timeout
appropriately.The timeout can also be set per connection from vcl as
sess.send_timeout
.
Statistics¶
- The
MAIN.sess_drop
counter is gone. It should be removed from any statistics gathering tools, if present - Added
rx_close_idle
counter for separate accounting whentimeout_idle
is reached. Also,send_timeout
is no longer reported as "remote closed".
vsl/logs¶
The
Process
timestamp forvcl_synth {}
was wrongly issued before the VCL subroutine, now it gets emitted after VCL returns for consistency withvcl_deliver {}
.Users of this timestamp should be aware that it now includes
vcl_synth {}
processing time and appears at a different position.A
Notice
VSL tag has been added
eof