Why is a 1G NIC transmitting at much higher speeds?
Issue
- Abnormally high
txkB/s
insar
output.
# sar -f /var/log/sa/sa14 -n DEV -s 12:00:00 -e 13:00:00
Linux 3.10.0-693.17.1.el7.x86_64 (localhost) 09/14/2018 _x86_64_ (8 CPU)
12:00:01 PM IFACE rxpck/s txpck/s rxkB/s txkB/s rxcmp/s txcmp/s rxmcst/s
12:10:01 PM lo 19.39 19.39 6.00 6.00 0.00 0.00 0.00
12:10:01 PM ens33 1698.07 7953.26 107.45 19378.04 0.00 0.00 0.00
12:20:01 PM ens192 0.18 0.00 0.01 0.00 0.00 0.00 0.00
12:20:01 PM lo 3921.78 3921.78 1114.73 1114.73 0.00 0.00 0.00
12:20:01 PM ens33 84182.81 1192887.93 30366.47 3043721.98 0.00 0.00 0.00
12:30:01 PM ens192 0.00 0.00 0.00 0.00 0.00 0.00 0.00
12:30:01 PM lo 3.37 3.37 0.67 0.67 0.00 0.00 0.00
12:30:01 PM ens33 228.71 714.81 14.60 1673.13 0.00 0.00 0.00
12:40:01 PM ens192 0.00 0.00 0.00 0.00 0.00 0.00 0.00
12:40:01 PM lo 5.81 5.81 1.35 1.35 0.00 0.00 0.00
12:40:01 PM ens33 62.21 170.10 4.91 391.78 0.00 0.00 0.00
12:50:01 PM ens192 0.00 0.00 0.00 0.00 0.00 0.00 0.00
12:50:01 PM lo 5.50 5.50 1.28 1.28 0.00 0.00 0.00
12:50:01 PM ens33 896.13 2446.59 55.93 5851.44 0.00 0.00 0.00
Average: ens192 0.04 0.00 0.00 0.00 0.00 0.00 0.00
Average: lo 787.51 787.51 223.67 223.67 0.00 0.00 0.00
Average: ens33 17078.74 239310.85 6090.09 610498.51 0.00 0.00 0.00
- The link seems to be mucher achieving faster speeds than what
ethtool
advertises. Is this a bug or some kind of reporting error?
Settings for ens33:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 0
Transceiver: internal
Auto-negotiation: on
MDI-X: off (auto)
Supports Wake-on: d
Wake-on: d
Current message level: 0x00000007 (7)
drv probe link
Link detected: yes
Environment
- Red Hat Enterprise Linux (RHEL)
- Virtual Machines with 1G NICs such as
e1000
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