Dell PowerStore Service Scripts Guide

This service script allows you to run a Linux tcpdump operation on a system interface for diagnostic purposes.

The output from this command is saved in rotating files of fixed size. When an output file grows either to the size defined by -C or to a different maximum size, the output is redirected to another file. This other file has the same base name but a different suffix. The suffix is a digit from 0 to the value defined by either the -W option or an internally defined maximum rotation value. Rotating files are created in numerical order.

Usage

Function	Diagnostic
Mode	Service
Usage	Service
Requires service user password?	Yes
Requires root privileges?	No
May cause data unavailability?	Yes
May cause data loss?	No
Scope	Node
Prerequisites	None

Format

svc_nas nas_svc_tcpdump [-h] [-i <interface>] [-w <file name>] 
[-W <rotations>] [-C <size>] [-s <number of bytes>] 
[-t {1,2,3,4}] [-v {1,2,3}] [-D] [-F <filter file>] [-e] [-n] [-q] 
[-T <timeout>] [-p <path>] [-y <data link type>] 
[-L] [-K <tcpdump session ID>]

Optional arguments

Qualifier	Description
-h, --help	Show the help message and exit.
-i, --interface	Specify the interface to be used to capture information. The default interface for the host namespace is mgmt0; for SDNAS, the default is eth_mgmt.
-w, --filename	Specify the base file name for the output files. The default name is dump.out.
-W, --rotations	Specify the number of files for output. The default is 5. The maximum number is 20.
-C, --size	Specify the size of each output file in MB. The default is 50. The maximum size is 200.
-s, --snaplen	Capture this specified number of bytes of data from each packet rather than the default 65535. 0 means the default value.
-t, --timestamp	Add the corresponding number (1, 2, 3, or 4) to the timestamp command to specify how you want the timestamp to appear in the output: Do not print a timestamp on each dump line. Print an unformatted timestamp on each dump line. Print a delta (in microseconds) between current and previous line on each dump line. Print a timestamp in the default format preceded by the date on each dump line.
-v, --verbosity	Specify the verbosity of the output, with 3 being most verbose.
-D, --dump_intfs	Print the list of the network interfaces available on the system and on which the tcpdump operation can capture packets.
-F, --input _expr	Use the file as input for the filter expression. The file should be in the tcpdump directory.
-e, --llheader	Print the link-level header on each dump line.
-n, --no_addr	Do not convert addresses such as host addresses, port numbers, and so on, to names.
-q, --quiet	Print abridged protocol information to make the output lines shorter.
-T, --timeout	Define the timeout before stopping the trace. The timeout format is xy, where x is a number and y is the unit of measurement for time (second, minute, hour, day). Some examples are 30s, 10m, 5h, 2d. If you want the trace to keep running, set the timeout to no. The default is no.
-p, --path	Specify the path for the output file storage; the default is /opt/sdnas/log/svc_output. The path that is specified must be an existing directory under /opt/sdnas/log/svc_output.
-y, --dlink	Set the data link type to datalinktype to use while capturing packets.
-L, --list	List active tcpdump sessions.
-K, --kill	Kill all tcpdump sessions or a specific session by designating its ID.