* telemetry: stack volume servers per cluster over time
The fleet-wide server count says how many volume servers reported, but not
who they belong to. Carry per-cluster counts in /api/cluster-sizes and draw
them the same way as cluster sizes, sharing one cluster ranking so a cluster
keeps its colour across both stacks.
* telemetry: drop the total disk usage chart from the dashboard
The stacked cluster sizes chart right below it has the same fleet total as
its stack height, plus the per-cluster breakdown. /api/metrics still serves
the aggregate for anyone graphing it elsewhere.
Short-lived clusters report once under a fresh raft topology id and never
again, so CI runs and demo stacks each become their own cluster. Held
forward for the whole active window they pile up, and the volume server
line climbs every day while capacity stays flat.
Sum the fleet series over confirmed clusters only, the same set the
version and OS charts already use.
* telemetry: total disk usage over time counted each cluster on one day
GetMetrics aggregated s.instances, which holds only each cluster's most
recent report. Every cluster therefore landed in a single date bucket --
the day it last reported on -- so the chart plotted the disk usage of
clusters that went silent that day, and piled the whole live fleet onto
today. Aggregate the daily histories instead, reusing the day alignment
that the per-cluster size series already does.
* telemetry: don't pad the charts with days the server has no history for
The dashboard asks for 30 days, but daily history only starts when a
server first collects it, so the charts opened on a run of zeros and then
jumped -- reading as a fleet that appeared overnight. Start the window at
the oldest sample on hand when it is younger than the requested range.
The dashboard charted one summed disk-usage line, so a step in the total
gave no hint which cluster moved. A new panel stacks each cluster's daily
size as its own band: the top of the stack is the fleet total, each band
is one cluster, and the clusters past the twentieth are summed into an
"other" band so the stack still adds up to the total.
The series is built from the per-cluster daily histories and served by
/api/cluster-sizes. Clusters report roughly once a day at no fixed hour,
so a day with no report carries the previous value forward — dropping it
to zero would sag the total every day as the clusters that have not
reported yet fall out from under it. A cluster that stops reporting past
the active window ends at its last sample instead of holding capacity
forever. Ranking is by the most recent day, tie-broken on cluster id so
the colors do not shuffle between refreshes.
Hover and click resolve to the band under the pointer: Chart.js's builtin
interaction modes match the nearest line, which on a stack of thin bands
is rarely the band being pointed at. Clicking one fills the per-cluster
history lookup below it.