On 21/02/2023 03:29, Christoph Anton Mitterer wrote:
Hey.
I wondered whether one can to with Prometheus something similar that
is possible with systems using RRD (e.g. Ganlia).
Depending on the kind of metrics, like for those from the node
exporter, one may want a very high sample resolution (and thus short
scraping interval) for like the last 2 days,... but the further one
goes back the less interesting those data becomes, at least in that
resolution (ever looked a how much IO a server had 2 years ago per 15s)?
What one may however want is a rough overview of these metrics for
those time periods longer ago, e.g. in order to see some trends.
For other values, e.g. the total used disk space on a shared
filesystem or maybe a tape library, one may not need such high
resolution for the last 2 days, but therefore want the data (with low
sample resolution, e.g. 1 sample per day) going back much longer, like
the last 10 years.
With Ganglia/RRD it one would then simply use multiple RRDs, each for
different time spans and with different resolutions... and RRD would
interpolate it's samples accordingly.
Can anything like this be done with Prometheus? Or is that completely
out of scope?
I saw that one can set the retention period, but that seems to affect
everything.
So even if I have e.g. my low resolution tape library total size,
which I could scrape only every hour or so, ... it wouldn't really
help me.
In order to keep data for that like the last 10 years, I'd need to set
the retention time to that.
But then the high resolution samples like from the node exporter would
also be kept that long (with full resolution).
Prometheus itself cannot do downsampling, but other related projects
such as Cortex & Thanos have such features.
--
Stuart Clark
--
You received this message because you are subscribed to the Google Groups
"Prometheus Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to prometheus-users+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/prometheus-users/f72674b0-a7de-ec89-955a-608b521cb754%40Jahingo.com.
