Often times when troubleshooting an issue it is useful to compare current data to data from a previous period. For example you observe high load on one machine and want to compare it to the load from a previous day. In the past you would simply open up two browser windows with data from each period and compare them. This may prove tricky as you may be dealing with different Y scales. To help with that we have recently added ability to overlay timeshifted data onto any host metric graph in Ganglia. What this means is that next to each metric graph you will see a button that says Timeshift. Clicking on it will overlay data from the same period prior to it e.g. if you are viewing hour it will overlay data from an hour ago, if you are viewing day it will overlay data from a day ago etc. For example this shows one minute load average overlaid with data from yesterday
whereas graph below displays data from a week ago overlaid over this weeks data
Preliminary support for this feature has already landed in the trunk of our Ganglia Web repository
It is full usable although we are working on refining it. This should be included in Ganglia Web 3.5.0 when it’s fully ready.