Best retention practice using Graphite - graphite

I have been a happy user of Graphite+Grafana for a few months now and I have been advocating it around my firm.
My approach has been to measure data of interest and collect them into 1-minute or 5-minute buckets and send that information to Graphite. I was recently contacted by a group that processes quotes (billions a day!) and their approach has been to create a log line each time their applications process 1 million quotes. The problem is that the interval between 2 log lines can be highly erratic from 1 second to a few hours.
The dilemma is then: should I set my retention policy to a 1-second bucket so that I can see all measurements associated with spikes or should I use say a 1-minute bucket so that the number of data points to be saved and later on queried is much more manageable. FYI, when I set it to 1-second, showing the data for 8 or 10 charts, for a few days was bringing the system (or at least my browser) to a crawl because of the numbers of data points (mostly NULL) being pushed around from Graphite to Grafana
Here's my retention policy: 1s:10d,1m:36d,5m:180d
Alternatively, is there a way to configure Grafana+Graphite to only retrieve non-NULL data points?
What do you recommend?

You can always specify a lower retention period for 1s metrics so when you show a longer range Graphite will send you only the more coarse level.
For example, you can specify: 1s:2d, 1m:7d, 5m:180d
This way, if you show a range more than 2 days in the past you will get 1m resolution (and so on), which won't make your browser crawl, while you will still be able to inspect spikes in the last 2 days.

Related

Graphite Not Showing Recent Data

I have Graphite running on a Docker container and I've fed 24 hours worth of data sampled at 20 minute intervals to nine metrics – far from being a large payload. If I graph each metric in the Graphite web app, the last six hours of data are invisible. If I pull the raw data from the render API, these data points are indeed null (timestamps with no value).
However, if I narrow the time range down to the last six hours, the graphs display all the data I would expect. Weirder still, if I try to view this data using Grafana, the same thing happens: the last six hours are not shown unless I shrink the time range.
Is there any way to fix this so that recent data points are visible while viewing more than 6 hours of data?
I would start by looking at the storage-schemas.conf and storage-aggregation.conf files.
Do you have a different retention after the 6 hour?
We had a similar issue with data disappearing after the first 24h where we had high resolution. We had to tune how data is aggregated to the "next level".
Or maybe it is just the data is not yet written to disk - and only exists in the carbon-cache at the moment.

Different Active Users count when using segments

I would love to understand what I'm looking at - why are the numbers different in this report when I add a segment?
This is the report without any segmentation:
This is the same report with the Mobile Traffic segment:
There two methods that Google uses to identify the number of users.
Calculation 1: Pre-calculated data
This calculation relies only on the number of sessions in the given date range and the time of each session. (This is determined by technology managed on the device, like a web browser, and is often referred to as the client-side time.) Because the result of this calculation can be added to the pre-aggregated data tables, Analytics can reference the table to quickly retrieve and serve this data in a report, including when you change the date range.
Calculation 2: Data calculated on the fly
Calculation 2 is based on the way you assign, collect, and store persistent data about your traffic. There are many solutions you can implement to customize this, but the most common way this data is going to be assigned and stored is through cookies managed via a web browser.
Adding a segment will force GA to calculate the data on the fly and that's why you are seeing a difference in the numbers.
Are you using GA free or 360? and the time range you are using is same in both reports?
You can also have a look into the Google article https://support.google.com/analytics/answer/2992042?hl=en
You are victim of sampling:
https://support.google.com/analytics/answer/2637192?hl=en
Sampling applies when:
you customize the reports
the number of sessions for the report time range exceeds 500K (GA) or 100M (GA 360)
The consequence is that:
the report will be based on a subset of the data (the % depends on the total number of sessions)
therefore your report data won't be as accurate as usual
What you can do to reduce sampling:
increase sample size in UI (will only decrease sampling to a certain extend, but in most cases won't completely remove sampling)
reduce time range
create filtered views so your reports contain the data you need and you don't have to customize them

Data sampling in google analytics goal flow report

The goal flow report on my google analytics account shows some strange sampling behavior. While I can usually select up to a month of data before sampling starts it seems to be different for the goal flow report.
As soon as I select more than one day of data the used data set is getting smaller very fast. At three days the report ist based on only 50% of the sessions, which, according to analytics, comes to only 35 sessions.
Has anyone experienced a similar behavior of sampling although only very small data-sets are used?
Sampling is induced when your request is calculation-intensive; there's no 'garunteed point at which it trips.
Goal flow complexity will increase exponentially as you add goals, so even a low number of goals might make this report demand a lot of processing.
Meanwhile you'll find that moast of the standard reports can cover large periods of time without sampling; they are preaggreated, so it's very cheap to load them.
If you want to know more about sampling, see here:
https://stackoverflow.com/a/37386181/5815149

Having trouble getting accurate numbers from graphite

I have an application that publishes a number of stats to graphite via statsd. One of the stats simply sends a stat increment to statsd every time a message is received by the service. I need to display a graph that shows the the relative traffic over time for this stat. Generally speaking, I should be able to display a graph that refreshes every, say 10 seconds, and displays how many messages were recived in those 10 seconds as well as the history for a given period of time. However, no matter how I format my API query I cannot seem to get accurate data. I've read a number of articles including this one:
http://code.hootsuite.com/accurate-counting-with-graphite-and-statsd/
That seems to give some good insight but is still not quite giving me what I need. this is the closes I have come:
integral(hitcount(stats.recieved, "10seconds"))
However, I don't like the cumulative result of this and when I run this I get statistics that come nowhere near to what I see n my logs for messages received. I am ok with accepting some packet loss but we talking about orders of magnitude. I know I am doing something wrong. Just hoping someone can give me some insight as to what.
A couple of things to check/try:
Configure Graphite for Statsd
Check to make sure that you've used the retention schema and aggregation settings in Graphite that match how Statsd will be sending data (i.e. it sends one data point per 10 second flush interval).
Run a single Statsd aggregator
Be sure you are only running one instance of Statsd as running multiple statsd daemons will cause metrics to be dropped (as Graphite will be configured to only store one data point for it's highest precision of 10s:6h)
Limit the time range in the UI or URL API to less than 6 hours
When displaying graphs with data that crosses over the 6 hour threshold (e.g. from now to 7 hours ago), you will begin seeing 1 minute worth of aggregated count data for the displayed graph (if you've configured Graphite for statsd with retentions = 10s:6h,1min:7d,10min:5y). Rollups will occur based on the oldest data point in the time range (e.g. now till 7+ days = you'll get 10 min rollups).
If sending sparse or "bursty" data AND displaying old time range (triggering aggregation)
Confirm that your xFilesFactor is low enough that aggregation produces non null values even with a high rate of nulls. For example, 100 requests in the first 10 seconds, and none for the remaining 50 seconds in a minute would cause a storage of 100, null, null, null, null, null which would be summed up to null when the data ages if the XFilesFactor is higher than 1/6. Using the statsd recommended graphite configuration handles this, but it is good to know about... as this can give the appearance of lost data.
Saving schema or aggregation changes
If you changed the graphite schema or aggregation settings after any metrics were stored (in whisper = graphite's storage) you'll need to either delete the .wsp files for the metric (graphite will recreate them) or run whisper-resize.py.
Validating settings
You can verify the settings against some whisper data by running whisper-info.py on a .wsp file. Find the .wsp file for one of your metrics in /graphite/storage/whisper/
Run: whisper-info.py my_metric_data.wsp. whisper-info.py output should tell you more about how the storage settings are working.
TLDR;
You should ensure that Graphite is set to store one data point per 10 second interval for metrics coming from StatsD. You should make sure that Graphite is summing (not averaging) for count data coming from Statsd. Both of these can be handled by using the recommended Statsd configuration settings. Don't run more than one Statsd aggregator. When using the UI, limit the data returned to less than 6 hours OR understand what rollup you are viewing when looking at data that crosses retention thresholds. Lastly, make sure the settings take (if you've already been sending metrics).

How does collection sampling affect the "live" stats for Google Analytics?

We've noticed lately that as our site is growing, our data in Google Analytics is getting less reliable.
One of the places we've noticed this most strongly is on the "Realtime Dashboard".
When we were getting 30k users per day, it would show about 500-600 people on line at a time. Now that we are hitting 50k users per day, it's showing 200-300 people on line at a time.
(Other custom metrics from within our product show that the user behavior hasn't changed much; if anything, users are currently spending longer on the site than ever!)
The daily totals in analytics are still rising, so it's not like it's just missing the hits or something... Does anyone have any thoughts?
The only thing I can think of is that there is probably a difference in interpretation of what constitutes a user being on line.
How do you determine if the user is on line?
Unless there is an explicit login/logout tracking, is it possible that it assumes that a user has gone if there is no user generated event or a request from the browser within an interval of X seconds?
If that is the case then it may be worth while adding a hidden iframe with some Javascript code that keeps sending a request every t seconds.
You can't compare instant measures of unique, concurrent users to different time-slices of unique users.
For example, you could have a small number of concurrent unique users (say 10) and a much higher daily unique users number like 1000, because 1000 different people were there over the course of the day, but only 10 at any given time. The number of concurrent users isn't correlated to the total daily uniques, the distribution over the course of the day may be uneven and it's almost apples and oranges.
This is the same way that monthly unique and daily uniques can't be combined, but average daily uniques are a lower bound for monthly uniques.

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