• Hostnames
• To Ganglia a new hostname is a new machine
• Has to resolve IP addresses so use DNS
• IP addresses stable
• Make sure you are not going to change IP addresses
• Time and date
• Make sure the time zone, time and date is consistent on all machines in a cluster
• Use of NTP is highly recommended
• So
• these are normal requirements on production machines
• for prototype and test systems – get this right before starting Ganglia
• Read the simple Ganglia How-To available for people setting up their first Ganglia system at:
• http://www.ibm.com/collaboration/wiki/display/WikiPtype/ganglia
  

Best Practices

• Preferred setup
• Ganglia sampling intervals
• Ganglia default ports
• Shared Ethernet adapter statistics
• Fibre Channel statistics
• Enhanced web interface

Best Practices – Preferred Setup

• Define each System p machine with all its LPARs as a separate cluster
• Use Unicast for network communication
• Define at least two LPARs per System p machine as gmond hosts for gmetad
• One would be sufficient, however, two is better for high availibility reasons
• Define those two LPARs in /etc/gmetad.conf as the information brokers for that machine
• From gmetad: Don’t poll the gmond hosts more frequently than every 15 seconds
• Know upfront what time intervals to use for sampling ("RRAs" stanza in /etc/gmetad.conf), see below
  
• Use my extensions for
• Ethernet adapters
• Fibre Channel adapters
• Web interface

Best Practices – Ganglia Sampling Intervals

• The sampling interval is defined in /etc/gmetad.conf.
• The "RRAs" stanza is used to defined individual settings.
• The sampling settings are global.
• If no "RRAs" stanza is defined a default configuration is used.
• For historic reasons all values are specified in intervals of 15 seconds.

Example: Default settings in Ganglia

• Take 240 samples at 1 × 15 seconds intervals (used for display of hour)
• Take 240 samples at 24 × 15 seconds (= 6 minutes) intervals (used for display of day)
• Take 240 samples at 168 × 15 seconds (= 42 minutes) intervals (used for display of week)
• Take 240 samples at 672 × 15 seconds (= 168 minutes) intervals (used for display of month)
• Take 370 samples at 5760 × 15 seconds (= 24 hours) intervals (used for display of year)

Example: 1-minute sampling for one year

• Take 525600 samples at 4 × 15 seconds (= 1 minute) intervals
• 525600 = 60 (samples/hour) × 24 (hours) × 365 (days) × 1 (year)

Example: 1-minute sampling for 6 months, 5-minute sampling for 2 years

• Take 259200 samples at every 4 × 15 seconds (= 1 minute) intervals
• 259200 = 60 (samples/hour) × 24 (hours) × 30 (days) × 6 (months)
• Take 210240 samples at every 20 × 15 seconds (= 5 minutes) intervals
• 210240 = 12 (samples/hour) × 24 (hours) × 365 (days) × 2 (years)

Example: 15-second sampling for 1 day, 1-minute sampling for 2 months, 10-minute sampling for 1 year

• Take 5760 samples at every 1 × 15 seconds intervals
• 5760 = 4 (samples/minute) 60 (samples/hour) × 24 (hours)
• Take 86400 samples at every 4 × 15 seconds (= 1 minute) intervals
• 86400 = 60 (samples/hour) × 24 (hours) × 30 (days) × 2 (months)
• Take 52560 samples at every 40 × 15 seconds (= 10 minutes) intervals
• 52560 = 6 (samples/hour) × 24 (hours) × 365 (days) × 1 (year)

Example: 1-minute sampling for 2 months, 5-minute sampling for 6 months, 15-minute sampling for 3 years

• Take 86400 samples at every 4 × 15 seconds (= 1 minute) intervals
• 86400 = 60 (samples/hour) × 24 (hours) × 30 (days) × 2 (months)
• Take 210240 samples at every 20 × 15 seconds (= 5 minutes) intervals
• 51840 = 12 (samples/hour) × 24 (hours) × 30 (days) × 6 (month)
• Take 105120 samples at every 60 × 15 seconds (= 15 minutes) intervals
• 105120 = 4 (samples/hour) × 24 (hours) × 365 (days) × 3 (years)

Best Practices – Default Ports

• 8649
• The port gmond uses for
• Sending to other gmonds via UDP (udp_send_channel in /etc/gmond.conf)
• Receiving from other gmonds via UDP (udp_receive_channel in /etc/gmond.conf)
• Sending an XML description of the state of the cluster (tcp_accept_channel in /etc/gmond.conf)
• 8651
• The port gmetad will answer requests for XML.
• 8652
• The port gmetad will answer queries for XML.
• This facility allows simple subtree and summation views of the XML tree.

Best Practices – Shared Ethernet Adapter Statistics

• The AIX libperfstat library seems not to report any statistics about Ethernet adapters if there are no interfaces defined on that adapter.
• Only seldom interfaces are defined on SEAs.
• The AIX command 'entstat' however provides these statistics.

• Korn shell script ‘ent_adapter.sh’
• Get it from http://www.perzl.org/ganglia/devicespecific.html
• Graphs will appear immediately for that specific host

Best Practices – Fibre Channel Statistics

• The AIX libperfstat library seems not to report any statistics about Fibre Channel adapters if there are no disks attached to the adapter.
• Tapes, for instance, would be left out.
• The AIX command 'fcstat' however provides these statistics.

• Korn shell script 'fcs_adapter.sh'
• Get it from http://www.perzl.org/ganglia/devicespecific.html
• Graphs will appear immediately for that specific host

Best Practices – Enhanced Web Interface