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Incorrect network stats reported in ifstat and sysstat

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Category:
ontap-9
Specialty:
perf
Last Updated:

Applies to

  • ONTAP 9.7
  • ONTAP 9.8
  • QLogic CNA card

Issue

  • Net out in sysstat -x 1 shows a much lower than expected network outbound throughput.
    Example:
    • On a Filer with steady 500MB/s read throughput, the Net out is only about 1MB/s
  • The physical NIC ports which are using QLogic CNA card display inaccurate TRANSMIT stats (Total bytes and Bytes/second) in  ifstat -a.
    Example
    • interface group a0a is comprised of 4 physical ports - e0c/e0d/e0e/eof in ifconfig -a
      a0a: flags=8843 metric 0 mtu 1500
              options=6407bb
              ether 02:a0:98:d2:c5:30
              hwaddr 02:a0:98:d2:c5:30
              pcp 1
              laggproto lacp lagghash l3
              laggport: e0e flags=1c
              laggport: e0f flags=1c
              laggport: e0c flags=1c
              laggport: e0d flags=1c

              groups: lagg
              media: Ethernet autoselect
              status: active
    • The heavy outbound throughput could be observed from the network layer but it’s only visible at VLAN a0a-6, it’s not available for the interface group a0a, or any underlying physical ports:

-- interface  a0a-6  (0 hours, 1 minute, 23 seconds) --
TRANSMIT
 Total frames:     1630k | Frames/second:   18955  | Total bytes:     46812m
 Bytes/second:      544m | Total errors:        0  | Errors/minute:       0

-- interface  a0a  (0 hours, 1 minute, 23 seconds) --
TRANSMIT
 Total frames:     1630k | Frames/second:   18955  | Total bytes:       106m
 Bytes/second:     1239k | Total errors:        0  | Errors/minute:       0

-- interface  e0c  (0 hours, 1 minute, 23 seconds) --
TRANSMIT
 Total frames:      235k | Frames/second:    2738  | Total bytes:     15361k
 Bytes/second:      178k | Total errors:        0  | Errors/minute:       0

-- interface  e0d  (0 hours, 1 minute, 23 seconds) --
TRANSMIT
 Total frames:    44094  | Frames/second:     513  | Total bytes:      2742k
 Bytes/second:    31895  | Total errors:        0  | Errors/minute:       0

-- interface  e0e  (0 hours, 1 minute, 23 seconds) --
TRANSMIT
 Total frames:     1340k | Frames/second:   15586  | Total bytes:     87814k
 Bytes/second:     1021k | Total errors:        0  | Errors/minute:       0

-- interface  e0f  (0 hours, 1 minute, 23 seconds) --
TRANSMIT
 Total frames:    10853  | Frames/second:     126  | Total bytes:       711k
 Bytes/second:     8273  | Total errors:        0  | Errors/minute:       0

 

Notes:

  • TRANSMIT Total bytes for interface group a0a is the sum of the TRANSMIT Total bytes from all the underlying physical ports
  • But TRANSMIT Total bytes for interface group a0a is a lot lower than the TRANSMIT Total bytes for the VLAN a0a-6

 

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