Propose other specification for line protocol usage

metrics/lineprotocol_alternative.md

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+# Overview
+
+ClusterCockpit uses the InfluxData line-protocol for collecting the node metric
+data.
+
+```
+<measurement>,<tag set> <field set> <timestamp [s]>
+```
+
+**Note**: This is a proposal for a different way to send & store the data!
+
+# Supported measurements:
+* `flops_sp`
+* `flops_dp`
+* `flops_any`
+* `load`
+* `mem_used`
+* `ipc`
+* `mem_bw`
+* `power`
+* `clock`
+* ...
+
+# Mandatory tags per measurement:
+* `hostname`
+* `type` in `[node, socket, cpu, (accelerator)]`
+* `type-id` for further specifying the type like CPU socket or HW Thread identifier
+
+# Optional tags depending on the measurment:
+* `device` for measurement `file_bw`
+* `device` for `net_bw` if splitting into `ib_bw` and `eth_bw` is not enough
+
+# Fields per measurement:
+The field key is always `value`
+
+# Optional measurements:
+If a fixed aggregation to a coarser granularity is desired, add addtional measurments to the same measurement with different tags:
+```
+mem_bw,hostname=X,type="socket",type-id=0 value=100.0
+mem_bw,hostname=X,type="socket",type-id=1 value=200.0
+```
+
+can additionally be send/stored as:
+
+```
+mem_bw,hostname=X,type="node",type-id=0 value=300.0
+```
+
+It is discussable where the type of aggregation should be encoded if required, either by adding a tag like `agg={min,max,sum,avg}` or using different fields like:
+
+```
+mem_bw,hostname=X,type="node",type-id=0 sum=300.0,min=100.0,max=200.0,avg=150.0
+```
+
+I prefer the separate `agg` tag because commonly, only a single type of aggregation is done per measurment (mostly `sum` but some require `avg` like `ipc`)