/proc/net/sockstat about netdata

[ktsaou]

[andyshinn]

When this is implemented, I would love if it supported the mem and orphan numbers from /proc/net/sockstat. This would be very helpful in tracking TCP: out of memory -- consider tuning tcp_mem errors for tuning /proc/sys/net/ipv4/tcp_mem.

[ktsaou]

These files are pretty simple to parse. I am not sure I know how to use this information though.

Can you find any reliable sources for each of the numbers in these files?

# cat /proc/net/sockstat
sockets: used 2152
TCP: inuse 66 orphan 0 tw 9 alloc 77 mem 6
UDP: inuse 17 mem 17
UDPLITE: inuse 0
RAW: inuse 0
FRAG: inuse 0 memory 0

This post says mem in TCP and UDP are in pages, while memory in FRAG is in bytes.

This post discusses about orphan, but I am not sure I understand. This one says that orphan sockets, are connections that are not attached to any user file handle.

This post describes out of memory errors and orphans, much better.

This is indeed very useful info!

[andyshinn]

I agree, it is a little hazy. I was using http://blog.tsunanet.net/2011/03/out-of-socket-memory.html as a reference which is helpful.

The TCP mem is in pages and directly correlates to /proc/sys/net/ipv4/tcp_mem (which is also in pages). I'll see if i can dig up information on FRAG, orphan, tw, and alloc as well.

[ktsaou]

here is the /proc/net/sockstat plugin.
Next is /proc/net/sockstat6.
I'll also try to implement the alarm.

[marcelmfs]

By the way my netdata aggregator server is showing the TCP: out of memory -- consider tuning tcp_mem in dmesg. RAM usage and the number of used sockets (not a huge sudden increase) during these error messages seem normal, maybe there's something else leaking TCP memory?