Please help with stuck BIND-9.9.11-P1 named process on rndc reconfig

[Sunghwan Kim(IBI)]

Hi BIND expert,



I could not have sent the followings thru https://www.isc.org/bind-
subscription-contact/

due to error on the site.



--------------

I am a S/W engineer who is working on BIND, especially named in Seoul/Korea.



I've got reports from a customer regarding stucked "named" process which had

not been performed any request from clients for 5 secs during "rndc
reconfig"

even if it is used to be finished in 700ms



24-Aug-2018 17:36:39.073 general: info: received control channel command
'reconfig'

¡Š..

24-Aug-2018 17:36:44.100 general: info: any newly configured zones are now
loaded



My customer's DNS server has been installing BIND-9.9.11-P1.



I would like to figure out why named was stucked for even 5 secs on rndc
reconfig.

I've figured out I/O event values(majflt/s) of SAR information on the
server is quite high

which is 58.34 even if it usually is 0.18 ~ 0.32.

The server information is as following;

1. OS : CentOS 7.3

2. CPU : Intel Xeon3.5Ghz 64bits(6 CPUs, 2 cores per CPU)

3. Mem. : 8G



Would you please give me any information about it ?

I know a lot of fixes on ¡°rndc reconfig¡± for latter version of 9.9.11-P1



Please take a look at the following logs from bind for your information;

=== general log =====

24-Aug-2018 17:36:39.073 general: debug 1: received control channel command
'null'

24-Aug-2018 17:36:39.073 general: info: received control channel command
'reconfig'

24-Aug-2018 17:36:39.073 general: info: loading configuration from
'/etc/named.conf'

24-Aug-2018 17:36:39.159 general: info: unable to open
'conf/named.iscdlv.key' using built-in keys

24-Aug-2018 17:36:39.168 general: info: using default UDP/IPv4 port range:
[9000, 61000]

24-Aug-2018 17:36:39.169 general: info: using default UDP/IPv6 port range:
[9000, 61000]

24-Aug-2018 17:36:39.190 general: info: sizing zone task pool based on 4704
zones

24-Aug-2018 17:36:39.293 general: debug 1: zone_settimer: zone xn--
pi5bm5e/IN: enter

¡Š.(removed)¡Š..

24-Aug-2018 17:36:41.809 general: debug 1: zone_settimer: zone xn--o78b/IN:
enter

24-Aug-2018 17:36:41.816 general: info: dns64 reverse zone: 0.0.0.0.0.0.0.0.
0.0.0.0.0.0.0.0.b.9.f.f.4.6.0.0.ip6.arpa.

¡Š.(removed)¡Š..

24-Aug-2018 17:36:43.927 general: debug 1: now using logging configuration
from config file

24-Aug-2018 17:36:43.935 general: info: zone
0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.b.9.f.f.4.6.0.0.ip6.arpa/IN: (master)
removed

24-Aug-2018 17:36:43.938 general: debug 1: load_configuration: success

24-Aug-2018 17:36:43.938 general: info: reloading configuration succeeded

¡Š¡Š¡Š¡Š



It would be appreciated if you share any hints, information.



Regards,

Sunghwan.



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