[Varnish] #1701: Bans keep increasing, despite ban lurker removing them

[Varnish]

#1701: Bans keep increasing, despite ban lurker removing them
--------------------+--------------------
 Reporter:  rbartl  |       Type:  defect
   Status:  new     |   Priority:  normal
Milestone:          |  Component:  build
  Version:  3.0.6   |   Severity:  normal
 Keywords:          |
--------------------+--------------------
 We have a high number of bans hitting our varnish cache.
 After some time running varnish those bans dont get deleted anymore.

 n_ban is ever increasing, and n_ban_retire is not changing.

 But Varnish Log reports ExpBan (AFAIK this is a notice that a ban gets
 marked as complete)
 {{{
 varnishlog | grep -i expban
    38 ExpBan       c 1971612403 was banned
    61 ExpBan       c 1971612483 was banned
    32 ExpBan       c 1971612438 was banned
    35 ExpBan       c 1971604741 was banned

 }}}


 Bans are increasing, and not retired ->
 {{{
 varnishstat -1 | grep -i ban ; sleep 120 ; varnishstat -1 | grep -i ban
 :(
 n_ban                    68391          .   N total active bans
 n_ban_gone               11743          .   N total gone bans
 n_ban_add               131903        14.37 N new bans added
 n_ban_retire             63512         6.92 N old bans deleted
 n_ban_obj_test        28425760      3097.16 N objects tested
 n_ban_re_test       3347374701    364717.23 N regexps tested against
 n_ban_dups               23818         2.60 N duplicate bans removed
 LCK.ban.creat                 19         0.00 Created locks
 LCK.ban.destroy                0         0.00 Destroyed locks
 LCK.ban.locks          203959983     22222.70 Lock Operations
 LCK.ban.colls                  0         0.00 Collisions
 n_ban                    68913          .   N total active bans
 n_ban_gone               12222          .   N total gone bans
 n_ban_add               132425        14.24 N new bans added
 n_ban_retire             63512         6.83 N old bans deleted
 n_ban_obj_test        28466827      3061.61 N objects tested
 n_ban_re_test       3420460198    367870.53 N regexps tested against
 n_ban_dups               24041         2.59 N duplicate bans removed
 LCK.ban.creat                 19         0.00 Created locks
 LCK.ban.destroy                0         0.00 Destroyed locks
 LCK.ban.locks          204014587     21941.77 Lock Operations
 LCK.ban.colls                  0         0.00 Collisions
 }}}

 When i call ban.list in varnishadm varnish hangs and gets restarted by its
 watcher  adm reports a 400 error) then the ban list is empty again of
 course.

 When does varnish "garbage"-collect the ban list ?

 Problem about this behaviour is that the ever increasing ban list is
 slowing down all requests.

 Regards, RB.

-- 
Ticket URL: <https://www.varnish-cache.org/trac/ticket/1701>
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