CentOS 7 System Running Out Of Available Memory, Then Unusable, Network Interfaces Probably Involved

Home » CentOS » CentOS 7 System Running Out Of Available Memory, Then Unusable, Network Interfaces Probably Involved
CentOS 2 Comments

Hello,

my CentOS 7 system goes unstable after few days of use, memory consumption growing and never getting freed, until the system slows down to hell (swapping), kills apps, and eventually freezes or reboots itself.

This only happens when I have two network interfaces turned on, one wired and one wireless, each to different routers.

The hardware: a Dell Precision 7530, SSD, 16GB RAM. HW memory and disk both tested OK by software. According to lspci:
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (7) I219-LM (rev 10)
6e:00.0 Network controller: Intel Corporation Wireless-AC 9260 (rev 29)

The software: I keep this CentOS 7 system up-to-date with the CR repo, excepted the microcode_ctl package, stuck to few versions back
(updating it kills the system and potentially causes fs damages). Kernels reproducing the issue (IOW, all):
kernel-3.10.0-1062.18.1.el7.x86_64
kernel-3.10.0-1127.el7.x86_64
kernel-3.10.0-1127.8.2.el7.x86_64
kernel-3.10.0-1127.13.1.el7.x86_64

Nothing jumps to my eyes looking at /var/log/messages but this, many occurrences:
kernel: nf_conntrack: falling back to vmalloc. I searched the Internet for it, and the few results I found were not bringing any solution and were quite pessimistic WRT to memory freeing, am I wrong?

Regards,

2 thoughts on - CentOS 7 System Running Out Of Available Memory, Then Unusable, Network Interfaces Probably Involved

  • nf_conntrack is only involved if you are doing some form of NAT routing on this system and/or fairly complex iptables kind of rules…. you mentioned two different network interfaces, one wired, one wireless, how are you using these, what sort of routing between the two networks ?

  • Hello John,

    On this machine I do not do anything at iptables or firewall level but opening ports for SSHD.

    The wired interface is directly bound to a 4G router (dhcp). The wireless one is connected to a LAN (wifi -> wifi AP -> wire -> switch ->
    wire -> router with iptables+dhcp -> wire -> xDSL box).

    Regards,