narotello's questions

When I tried to find ip_conntrack of nf_conntrack files in /proc on my server I found I bunch of files, which are for some reason specific per-pid, e.g.:

/proc/2507/task/2507/net/stat/ip_conntrack
/proc/2507/task/2507/net/stat/nf_conntrack
/proc/2507/net/stat/ip_conntrack
/proc/2507/net/stat/nf_conntrack

What is the need for having such files in /proc for specific task?
Seems that conntrack statistics is common for the entire kernel and all tasks.. Some counters are per-CPU, but not per-task..

From this question Statistics /proc/net/stat/nf_conntrack is missing on Linux server I recognized that /proc/net/stat/nf_conntrack has an alternative conntrack -S.
In /proc/net/stat/nf_conntrack there is NEW counter, based on which the one can calculate CPS (connections per second) metric. But in conntrack -S I see no such a counter.

How can I obtain the NEW conntrack counter without /proc/net/stat/nf_conntrack? Is there a way to obtain it from conntrack -S?

For some reason I have no such file on my server..

root@serv:~# uname -a
Linux serv 5.4.0-87-generic #98~18.04.1-Ubuntu SMP Wed Sep 22 10:45:04 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
root@serv:~# cat /proc/net/stat/nf_conntrack
cat: /proc/net/stat/nf_conntrack: No such file or directory

But my conntrack is definitely enabled:

root@serv:~# lsmod | grep conntr
xt_conntrack           16384  1
nf_conntrack_netlink    45056  0
nf_conntrack          139264  2 xt_conntrack,nf_conntrack_netlink
nf_defrag_ipv6         24576  1 nf_conntrack
nf_defrag_ipv4         16384  1 nf_conntrack
libcrc32c              16384  1 nf_conntrack
nfnetlink              16384  1 nf_conntrack_netlink
x_tables               45056  3 xt_conntrack,iptable_filter,ip_tables

And conntrack -L works perfectly.
But lnstat -f ip_conntrack also shows the empty output.
What is the reason? Should I insert some kernel module for this file to appear in procfs?

I want to analyze my Debian 9 server's network workload to detect some possible network overloads.

The main metrics I need to analyze are:

• CPS (connections per second)
• Throughput

Is there a way to obtain these metrics from within Linux?
I thought that CPS metric could be somehow obtained through conntrack NEW connections events but not sure that this would be the most proper way..

Sorry if obvious.

P.S. this server handles not only local traffic, it also forward a lot of traffic.