Changes between Version 33 and Version 34 of GEMINIv1.1Tutorial

10/23/12 10:14:59 (8 years ago)
Ahmed El-Hassany



  • GEMINIv1.1Tutorial

    v33 v34  
    562562 - as appropriate, store analyzed results and/or visualization in storage service
     565==== 5.1 . Visualize Measurement Data ====
     567Doing the user experiment should have given the scheduled active measurements enough time to gather some data. We also generated some heavy traffic during our iperf data transfers. This section of the tutorial covers how to visualize the data for regular active tests. We will also check the passive monitoring graphs again to see how the iperf transfers affected our hosts.
     569===== 5.1.1 Accessing perfAdmin for Active Measurements Data =====
     571To query and visualize the active measurements data we will use perfAdmin. perfAdmin is a web service that is able to query perfSONAR services and plot relevant data. You can access a perfAdmin instance running on your slice through the portal or by going to https://<gn node>/perfAdmin (note the capitalization).
     575There are two sides to perfAdmin. The first side of perfAdmin is showing which services have registered to UNIS and are thus "known". The other side is querying a perfSONAR service (or set of services) for measurement data and displaying it to users.
     577The landing page will show which services we know about from the information on UNIS. If this is your first time opening this page, you will probably be greeted with a blank page. The services should have had enough time to start and register themselves with UNIS. We pull the information from UNIS (make sure the last fetched date changes) and then refresh the page to make sure we have the latest information.
     581After doing this we should see all the services we enabled during the configuration section for active services. ''NOTE: There are many reason why services might not show: pSConfig on the node hasn't pulled the configuration from UNIS yet (see Apply Config above); the services didn't have any data to register with UNIS (services usually register every 30 minutes or when changes are detected); or there might be a problem talking to UNIS. Please contact us if you're having trouble.''
     585On the list of services we can see the tool daemons for OWAMP and BWCTL. We can also see the perfSONAR services storing the Ping and OWAMP data from the tests we've configured. From this page we can query a given service to see the corresponding data. The active measurement data is stored on the node that initiates the measurements and is served by a perfSONAR service running on that node. For example, we can query the perfSONAR BUOY OWAMP MA on node PCA to see the OWAMP data from PCA to PCB.
     587''NOTE: When querying a single service, perfAdmin will first fetch all the metadata stored on that service. After obtaining the metadata, perfAdmin queries the service for data in order to build summaries and distinguish between active and inactive data sets. This process may take some time if there are many measurements stored on a given service.''
     591In this particular case we only have one OWAMP measurement stored at this service. We can graph by selecting a time range from the select box. perfAdmin will query the service for all data points within the last X hours and plot those (data points might be aggregated depending on granularity). The graphs are a little bit interactive, e.g. you can mouse over different data points and see the values for each direction.
     595The graph above shows two spikes measured latency and a lost packet during one of those. These spikes correspond to the iperf data transfers where we were saturating the links.
     597We can access the Ping data from our scheduled test in a similar way. Going back to our Registered Services page, this time we access the PingER service on node PCC.
     601While it's good to be able to query each service for its data, sometimes it's better to have access to all measurements in our slice on the same page. perfAdmin provides this option on the left menu for each of the regular testing measurement types currently supported (One-way Delay, Ping and Throughput). When we access one of these pages, perfAdmin will query each known service storing measurements of the given type for all the related metadata. It then builds a single page that we can use to query for a particular measurement's data. For example, if we go to the One-Way Delay page we should be able to see the measurements stored in both nodes PCA and PCC.
     605===== 5.1.2 Changes in Passive Monitoring Graphs =====
     607Using the GEMINI Portal, you can also view the changes in Passively monitored Network traffic and system resources when running any experiment or traffic or any other kind of load on the nodes in your slice.