16 Bře
2018
16 Bře
'18
10:32
Hi Daniel, hi all.
I completely agree that VmSize is not the right metric and I was not
mentioning it in my original post :-) I'd rather point out that Knot is
in my case consuming nearly 2Gig of RAM while serving just 141 zones
with 1MB of records while Bind serving 1560 zones (10% on DNSSEC)
something about 550MB =-O
root@eira:~# free -h
total used free shared buff/cache
available
Mem: 2.0G 1.7G 122M 5.4M 126M 109M
Swap: 0B 0B 0B
root@eira:~#
root@eira:~# systemctl stop knot.service
root@eira:~#
root@eira:~# free -h
total used free shared buff/cache
available
Mem: 2.0G 54M 1.8G 5.4M 126M 1.8G
Swap: 0B 0B 0B
root@eira:~#
Is it something what I have to count on when using Knot? I am just
surprised by such memory requirements and your measurement shows that it
is like that. I will have to add some RAM...
Thanks for memory saving tips.
BR
Ales
On 15.3.2018 21:16, daniel.salzman(a)nic.cz wrote:
Hi Aleš,
I would agree with Vladimír. Virtual memory consumption is not
important. We should focus on physical memory consuption (VmRSS).
But in your case, these values are almost equal. It's very strange!
I did a quick measurement:
TLD with DNSSEC | 10k zones with DNSSEC
VIRT RES | VIRT RES
--------------------------------+-----------------
Bind 9.12.1 656M 419M | 1269M 152M
Knot 2.6.5 4384M 360M | 4588M 39440
NSD 4.1.20 124M 87216 | 147M 108M
1759M 1732M | 115M 89124
Note1: I don't know how NSD work, so I printed 2 top level processes.
Note2: Bind was compiled with --enable-threads.
The virtual memory consumption by Knot can be significantly reduced by
setting max-timer-db-size, max-journal-db-size, max-kasp-db-size, and
--with-conf-mapsize configure option (if compiled from the source code).
Best,
Daniel
On 2018-03-15 13:37, Aleš Rygl wrote:
> Dear all,
>
> While trying to migrate or DNS to Knot I have noticed that a slave
> server with 2GB RAM is facing memory exhaustion. I am running
> 2.6.5-1+0~20180216080324.14+stretch~1.gbp257446. There is 141 zones
> having around 1MB in total. Knot is acting as pure slave server with
> minimal configuration.
>
> There is nearly 1.7GB of memory consumed by Knot on a freshly
> rebooted server:
>
> root@eira:/proc/397# cat status
> Name: knotd
> Umask: 0007
> State: S (sleeping)
> Tgid: 397
> Ngid: 0
> Pid: 397
> PPid: 1
> TracerPid: 0
> Uid: 108 108 108 108
> Gid: 112 112 112 112
> FDSize: 64
> Groups: 112
> NStgid: 397
> NSpid: 397
> NSpgid: 397
> NSsid: 397
> VmPeak: 24817520 kB
> VmSize: 24687160 kB
> VmLck: 0 kB
> VmPin: 0 kB
> VmHWM: 1743400 kB
> VmRSS: 1743272 kB
> RssAnon: 1737088 kB
> RssFile: 6184 kB
> RssShmem: 0 kB
> VmData: 1781668 kB
> VmStk: 132 kB
> VmExe: 516 kB
> VmLib: 11488 kB
> VmPTE: 3708 kB
> VmPMD: 32 kB
> VmSwap: 0 kB
> HugetlbPages: 0 kB
> Threads: 21
> SigQ: 0/7929
> SigPnd: 0000000000000000
> ShdPnd: 0000000000000000
> SigBlk: fffffffe7bfbbefc
> SigIgn: 0000000000000000
> SigCgt: 0000000180007003
> CapInh: 0000000000000000
> CapPrm: 0000000000000000
> CapEff: 0000000000000000
> CapBnd: 0000003fffffffff
> CapAmb: 0000000000000000
> Seccomp: 0
> Cpus_allowed: f
> Cpus_allowed_list: 0-3
> Mems_allowed: 00000000,00000001
> Mems_allowed_list: 0
> voluntary_ctxt_switches: 260
> nonvoluntary_ctxt_switches: 316
> root@eira:/proc/397#
>
> Config:
>
> server:
> listen: 0.0.0.0@53
> listen: ::@53
> user: knot:knot
>
> log:
> - target: syslog
> any: info
> mod-rrl:
> - id: rrl-10
> rate-limit: 10 # Allow 200 resp/s for each flow
> slip: 2 # Every other response slips
>
> mod-stats:
> - id: custom
> edns-presence: on
> query-type: on
> request-protocol: on
> server-operation: on
> request-bytes: on
> response-bytes: on
> edns-presence: on
> flag-presence: on
> response-code: on
> reply-nodata: on
> query-type: on
> query-size: on
> reply-size: on
>
>
> template:
> - id: default
> storage: "/var/lib/knot"
> module: mod-rrl/rrl-10
> module: mod-stats/custom
> acl: [allowed_transfer]
> disable-any: on
> master: idunn
>
> I was pretty sure that a VM with 2GB RAM is enough for my setup :-)
>
> BR
>
> Ales