Transcript of Troubleshooting. Tools © 2012 Citrix | Confidential – Do Not Distribute Troubleshooting Tools...
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- Troubleshooting
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- Tools
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Tools Inspecting HTTP Headers In many cases it is useful to view
the HTTP headers when debugging various problems, including:
Persistence failures when using cookie persistence Performing
caching and tuning cache headers Verifying compression is occurring
Isolating authentication issues Many tools that are available are
very useful for this task and are easy to use: Live HTTP Headers
for Mozilla/Firefox IE HTTP Headers for Internet Explorer
IEHTTPAnalyzer Fiddler
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Tools Inspecting HTTP Headers: Live HTTP Headers Live HTTP Headers
is available at http://livehttpheaders.mozdev.org free
toolhttp://livehttpheaders.mozdev.org Once installed, go to Tools
> livehttpheaders to start capturing headers. Once opened, all
HTTP request and response headers will be displayed, as shown. If
desired, you can also filter what requests will be captured.
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Tools Inspecting HTTP Headers: IE HTTP Headers IE HTTP Headers can
be downloaded from http://www.bluck.info/iehttpheaders - free
toolhttp://www.bluck.info/iehttpheaders After installation, go to
View > Explorer Bar > ieHTTPHeaders to display the view
pane.
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Inspecting HTTP Headers IEHTTPAnalyzer - must purchase (found on
student Desktop) or download from
http://www.ieinspector.com/httpanalyzer/http://www.ieinspector.com/httpanalyzer/
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Inspecting HTTP Headers Fiddler - Freeware Download from
http://www.fiddler2.com/fiddler2/http://www.fiddler2.com/fiddler2/
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- Tracing
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Tools Packet captures can be done on the NetScaler via the new
trace option on the diagnostics tab, as shown
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Tools The dialog to perform a trace has several options: Packet
size: Specify 0 to capture the entire packet Duration of data per
file: By default 1 hr. Format: Select tcpdump to capture in pcap
format Filter expression: TCPDUMP capture filter to only capture
certain packets being processed Capturing mode: Additional options
for capturing packets
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Tools Packet Traces, continued Once a trace is performed, the trace
will have to be downloaded
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Tools Packet Traces, continued Select where you want the trace
saved and open with your favorite trace tool
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- 2012 Citrix | Confidential Do Not Distribute Network Traffic
Capture The nstrace utility: Is used for packet capture on the
NetScaler system Has files stored in /var/nstrace Has names
nstracexx.cap (Native) or nstracexx.pcap (tcpdump) Has syntax
nstrace.sh sz 0 Prefers the native format for packet capture since
it captures more information Can view the native NetScaler and pcap
format with Wireshark
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- 2012 Citrix | Confidential Do Not Distribute Sample nstrace.sh
Output
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- SNMP
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Tools SNMP Overview SNMP is a standard means of receiving
information from a device by either polling variables (OIDs) or
receiving alerts (traps). The NetScaler system provides a list of
over a thousand variables in a MIB file. In some devices, SNMP can
both read data and write configurations, but with the NetScaler
system it is read only. Common tools that are used to keep track
and plot long-term SNMP data include NetScaler Command Center, HP
OpenView and MRTG.
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Tools SNMP Community Configuration The first step in monitoring via
SNMP is to configure a community and permission (select ALL).
System -> SNMP -> Community
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Tools SNMP Manager Configuration To limit SNMP polling to a set of
IPs or networks, configure managers as well.
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Tools Network Monitoring with SNMP Some of the most commonly polled
SNMP OIDs HA State:.1.3.6.1.4.1.5951.4.1.1.6.0 Average
CPU:.1.3.6.1.4.1.5951.4.1.1.41.1.0 Memory Utilization
(%):.1.3.6.1.4.1.5951.4.1.1.41.2.0 Server
Connections:.1.3.6.1.4.1.5951.4.1.1.46.1.0 Client
Connections:.1.3.6.1.4.1.5951.4.1.1.46.2.0 HTTP
Requests:.1.3.6.1.4.1.5951.4.1.1.48.67.0 HTTP
Responses:.1.3.6.1.4.1.5951.4.1.1.48.53.0 Interface Stats
(table):.1.3.6.1.4.1.5951.4.1.1.54 Since many OIDs are dynamically
generated, tools such as the iReasoning MIB browser
(http://www.iReasoning.com) are handy for locating
them.http://www.iReasoning.com
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- 2012 Citrix | Confidential Do Not Distribute Troubleshooting
Most Common Issues Do not rule out basic problems. Is there a
duplex mismatch? #1 cause of poor performance Is a feature enabled?
Check routing, in particular when USIP is enabled. Do not assume
coders follow HTTP? Does it work as TCP? When installing a
NetScaler system, do not assume the rest of the network is correct
it usually is broken in subtle ways. Divide and conquer. Try to
break the problem down into pieces, and verify each. Always perform
a trace when you have a problem. A trace tells you what IS
happening and not what you think should be happening.
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- Logs
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- 2012 Citrix | Confidential Do Not Distribute Logged Information
The following components enable recording and extracting
information for troubleshooting the NetScaler: nsconmsg
newnslog
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- 2012 Citrix | Confidential Do Not Distribute Nsconmsg Command
Output
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- 2012 Citrix | Confidential Do Not Distribute Accessing Logged
Information The log file and time parameters should be replaced
with the necessary values to obtain desired log information The log
file and time parameters are available to: Uncompress an archived
log file Discover the time period covered by the log View
load-balancing statistics from the archived log Extract logging
information for a shorter duration Start log process for
newnslog
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- 2012 Citrix | Confidential Do Not Distribute Displaying Console
Messages
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- 2012 Citrix | Confidential Do Not Distribute Calendar
Dialog
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- 2012 Citrix | Confidential Do Not Distribute Sample nsconmsg
Output Using grep
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- 2012 Citrix | Confidential Do Not Distribute Displaying Event
Information
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- 2012 Citrix | Confidential Do Not Distribute Displaying CPU
Information
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- 2012 Citrix | Confidential Do Not Distribute Displaying NIC
Statistics
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- 2012 Citrix | Confidential Do Not Distribute Load Balancing
Display Output
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- Statistics
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- 2012 Citrix | Confidential Do Not Distribute Statistics
Monitoring statistics of the NetScaler system or a feature can be
obtained by running the stat command Stat feature displays summary
statistics for the feature Additional stat parameters are: detail:
for detailed feature statistics fullValues: for number and strings
displayed in full form ntimes: for number of times statistics to be
displayed logFile: for reading stats from a log file names
internal: for viewing internal counter names
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- 2012 Citrix | Confidential Do Not Distribute Displaying
Statistics in the CLI -stat command: Provides statistics on certain
components of a NetScaler system -E.g.: - stat cpu - stat system -
stat lb vserver
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- 2012 Citrix | Confidential Do Not Distribute NetScaler System
Statistical Utility
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- Work better. Live better.