high rx and dropped errors

Question

I connected an IXIA appliance with an ethernet interface with a span port:

With ifconfig -a I see this situation:

Link encap:Ethernet  HWaddr 00:19:99:0b:0b:00
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:5408388104 errors:3027294504 dropped:5408388104 overruns:0 frame:3027294504
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:3338770841558 (3.0 TiB)  TX bytes:0 (0.0 B)
          Memory:ce320000-ce33ffff

And with ethtools

testss:~# ethtool -S eth6
NIC statistics:
     rx_packets: 5409242132
     tx_packets: 0
     rx_bytes: 3382468530625
     tx_bytes: 0
     rx_broadcast: 7414514
     tx_broadcast: 0
     rx_multicast: 139336057
     tx_multicast: 0
     multicast: 139336057
     collisions: 0
     rx_crc_errors: 0
     rx_no_buffer_count: 0
     rx_missed_errors: 0
     tx_aborted_errors: 0
     tx_carrier_errors: 0
     tx_window_errors: 0
     tx_abort_late_coll: 0
     tx_deferred_ok: 0
     tx_single_coll_ok: 0
     tx_multi_coll_ok: 0
     tx_timeout_count: 0
     rx_long_length_errors: 3027655624
     rx_short_length_errors: 0
     rx_align_errors: 0
     tx_tcp_seg_good: 0
     tx_tcp_seg_failed: 0
     rx_flow_control_xon: 0
     rx_flow_control_xoff: 0
     tx_flow_control_xon: 0
     tx_flow_control_xoff: 0
     rx_long_byte_count: 3382468530625
     tx_dma_out_of_sync: 0
     tx_smbus: 0
     rx_smbus: 0
     dropped_smbus: 0
     os2bmc_rx_by_bmc: 0
     os2bmc_tx_by_bmc: 0
     os2bmc_tx_by_host: 0
     os2bmc_rx_by_host: 0
     tx_hwtstamp_timeouts: 0
     rx_hwtstamp_cleared: 0
     rx_errors: 3027655624
     tx_errors: 0
     tx_dropped: 0
     rx_length_errors: 3027655624
     rx_over_errors: 0
     rx_frame_errors: 0
     rx_fifo_errors: 0
     tx_fifo_errors: 0
     tx_heartbeat_errors: 0
     tx_queue_0_packets: 0
     tx_queue_0_bytes: 0
     tx_queue_0_restart: 0
     tx_queue_1_packets: 0
     tx_queue_1_bytes: 0
     tx_queue_1_restart: 0
     tx_queue_2_packets: 0
     tx_queue_2_bytes: 0
     tx_queue_2_restart: 0
     tx_queue_3_packets: 0
     tx_queue_3_bytes: 0
     tx_queue_3_restart: 0
     tx_queue_4_packets: 0
     tx_queue_4_bytes: 0
     tx_queue_4_restart: 0
     tx_queue_5_packets: 0
     tx_queue_5_bytes: 0
     tx_queue_5_restart: 0
     tx_queue_6_packets: 0
     tx_queue_6_bytes: 0
     tx_queue_6_restart: 0
     tx_queue_7_packets: 0
     tx_queue_7_bytes: 0
     tx_queue_7_restart: 0
     rx_queue_0_packets: 5409242130
     rx_queue_0_bytes: 3339194591572
     rx_queue_0_drops: 0
     rx_queue_0_csum_err: 0
     rx_queue_0_alloc_failed: 0
     rx_queue_1_packets: 0
     rx_queue_1_bytes: 0
     rx_queue_1_drops: 0
     rx_queue_1_csum_err: 0
     rx_queue_1_alloc_failed: 0
     rx_queue_2_packets: 0
     rx_queue_2_bytes: 0
     rx_queue_2_drops: 0
     rx_queue_2_csum_err: 0
     rx_queue_2_alloc_failed: 0
     rx_queue_3_packets: 0
     rx_queue_3_bytes: 0
     rx_queue_3_drops: 0
     rx_queue_3_csum_err: 0
     rx_queue_3_alloc_failed: 0
     rx_queue_4_packets: 0
     rx_queue_4_bytes: 0
     rx_queue_4_drops: 0
     rx_queue_4_csum_err: 0
     rx_queue_4_alloc_failed: 0
     rx_queue_5_packets: 0
     rx_queue_5_bytes: 0
     rx_queue_5_drops: 0
     rx_queue_5_csum_err: 0
     rx_queue_5_alloc_failed: 0
     rx_queue_6_packets: 0
     rx_queue_6_bytes: 0
     rx_queue_6_drops: 0
     rx_queue_6_csum_err: 0
     rx_queue_6_alloc_failed: 0
     rx_queue_7_packets: 0
     rx_queue_7_bytes: 0
     rx_queue_7_drops: 0
     rx_queue_7_csum_err: 0
     rx_queue_7_alloc_failed: 0

Is it a cable issue?

After changing MTU the dropped value only increased

Link encap:Ethernet HWaddr 00:19:99:0b:0b:00
    UP BROADCAST RUNNING PROMISC MULTICAST MTU:9000 Metric:1
    RX packets:5957084917errors:3175605334 dropped:5957084919 overruns:0 frame:3175605334
    TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:1000
    RX bytes:3338770841558 (3.0 TiB)
    TX bytes:0 (0.0 B)
    Memory:ce320000-ce33ffff

Solution

Yes, cable, connector/SFP, link or NIC issue (in the order of most probable) is the most common cause for rx errors.

EDIT:

...however - the majority of the errors are long frame errors which leads me to believe that your Linux machine is configured for an MTU of 1500 but your directly attached ethernet switch is configured to use jumbo frames (ie. >9000 bytes).

Raise your Linux MTU to match your switch's or, if your NIC doesn't support jumbo frames, change the MTU on your switch. If you're running Cisco:

conf t
int Gi 1/0/1
mtu 1500

In case you're using a different vendor, consult your user manual

Comments

[ELK2]

Thanks for you answer. Can you explain me how you can guess this?

[Jonas Bjork]

It's just the most common cause for rx-errors. However, read my edit regarding jumbo frames.

[ELK2]

Thanks. I changed the MTU size to 9000. Now errors are stopped but dropped continue to increase. ink encap:Ethernet HWaddr 00:19:99:0b:0b:00 UP BROADCAST RUNNING PROMISC MULTICAST MTU:9000 Metric:1 RX packets:5957084917errors:3175605334 dropped:5957084919 overruns:0 frame:3175605334 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3338770841558 (3.0 TiB) TX bytes:0 (0.0 B) Memory:ce320000-ce33ffff

[Jonas Bjork]

What kind of drops? Edit your original message with the new values