Skip to main content
NetApp Knowledge Base

Incorrect network stats reported in ifstat and sysstat

Views:
639
Visibility:
Public
Votes:
0
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

 

Sign in to view the entire content of this KB article.

New to NetApp?

Learn more about our award-winning Support

NetApp provides no representations or warranties regarding the accuracy or reliability or serviceability of any information or recommendations provided in this publication or with respect to any results that may be obtained by the use of the information or observance of any recommendations provided herein. The information in this document is distributed AS IS and the use of this information or the implementation of any recommendations or techniques herein is a customer's responsibility and depends on the customer's ability to evaluate and integrate them into the customer's operational environment. This document and the information contained herein may be used solely in connection with the NetApp products discussed in this document.