Description of problem: On cluster monitored by WA more than one whole day but less than 7 days, panels Weekly Growth Rate and Weeks Remaining shows inaccurate/meaningless values. When the cluster is running less than one day, both mentioned panels shows correctly N/A. When the cluster is running more than 7 days, the values for Weekly Growth Rat and Weeks Remaining are correctly calculated. Version-Release number of selected component (if applicable): RHGS WA Server: collectd-5.7.2-3.1.el7rhgs.x86_64 collectd-ping-5.7.2-3.1.el7rhgs.x86_64 grafana-4.3.2-3.el7rhgs.x86_64 graphite-web-0.9.15-1.el7rhgs.noarch libcollectdclient-5.7.2-3.1.el7rhgs.x86_64 tendrl-ansible-1.6.3-7.el7rhgs.noarch tendrl-api-1.6.3-5.el7rhgs.noarch tendrl-api-httpd-1.6.3-5.el7rhgs.noarch tendrl-commons-1.6.3-12.el7rhgs.noarch tendrl-grafana-plugins-1.6.3-11.el7rhgs.noarch tendrl-grafana-selinux-1.5.4-2.el7rhgs.noarch tendrl-monitoring-integration-1.6.3-11.el7rhgs.noarch tendrl-node-agent-1.6.3-10.el7rhgs.noarch tendrl-notifier-1.6.3-4.el7rhgs.noarch tendrl-selinux-1.5.4-2.el7rhgs.noarch tendrl-ui-1.6.3-11.el7rhgs.noarch How reproducible: 100% Steps to Reproduce: 1. Prepare Gluster Storage Cluster and RHGS WA Server. 2. Import Gluster Cluster into WA. 3. Leave it running for more than 1 day but less than 7 days without any traffic on the storage nodes. Actual results: The Weekly Growth Rate panel for particular volume shows for example 2.0 GiB. The Weeks Remaining panel for particular volume shows for example 89. Expected results: As the cluster is running less than 7 days, it should shows N/A for both values. Additional info: The "diffSeries(#B, #A)" function used in Grafana to calculate the values returns meaningless value instead of N/A, if the first input contains correct data, but the second one is N/A (which happened when the cluster is running more than 1 day, but less than a week).
Created attachment 1490864 [details] Weekly Growth Rate and Weeks Remaining panels on 2 days old cluster
Created attachment 1490865 [details] Graphite graphs of usable_capacity and used_capacity for 2 days old cluster
There is a similar problem with Brick dashboard. While it correctly shows "Weeks Remaining" value as "Insufficient data collected for forecast" if there was no traffic on this node, it gives a misleading value if there was some traffic. For example, I ran the test that increased brick capacity utilization from 0% to 90% within an hour, and it caused the dashboard to show 101 as the value of "Weeks Remaining".
Created attachment 1508254 [details] Misleading value of Weeks Remaining