Forum Discussion
Render operator ignoring ymin and ymax values
Hey Clive,
Yes it is a busy chart, I have extra WHERE statements similar to yours in the Query I'm actually using that filter our a bunch of the disks that I'm not particularly interested in (Azure VM BEK and Temp storage drives especially) however I've left those out of my post as it identifies some of the machine names (and therefore could be extrapolated to the DNS name with enough trial and error).
The issue with just using:| where InstanceName has ":".......and specifying specific drive letters is that the Azure BEK encryption drives don't seem to always end up with the same drive letter, so my WHERE statement has to be a bit more complex to pick specific drives from certain machines.
Back on topic, the make-series statement that you suggested yesterday has worked perfectly to get the y axis to go from 0 - 100, it also allowed me to give the Y axis a custom name label which I hadn't yet worked out how to do.
I also used this extend and strcat() statement to create a new series for the X axis with a better name and data that reads easier in the legend:
| extend DiskName = strcat(Computer," (", InstanceName,")")You might have noticed I then used the new series in my version of your make-series to spilt the X series up the way I wanted.
After all that, I've ended up with something very similar to this:
Perf | where TimeGenerated > ago(60d) | where ObjectName == "LogicalDisk" | where CounterName == "% Free Space" | where InstanceName == "C:" or InstanceName == "F:" or InstanceName == "E:" | extend DiskName = strcat(Computer," (", InstanceName,")") | make-series DiskFreeSpace = max(CounterValue) default=0 on TimeGenerated in range(ago(60d), now(), 12h) by DiskName | render timechart title ="Virtual Machine Disk Usage"Which results in this:
The data is quite spiky as the VMs are all relatively new, so the series will smooth out over a couple of months, and I still have some work to do to try and get it to display in local time (+12 GMT NZST), move the legend to the bottom (more like the built in Azure charts) and remove the dots off the series lines....... but fundamentally, this gives me what I need.
Thank you very much for you help! I'm learning a lot as I go!
I have a similar issue trying to graph free space on the Logical drives of all my Azure VMs, my data set luckily has the right values to push the ymax to 100 on it's own, but it's ignoring the ymin = 0 (or any ymax other than 100) that I'm trying to define.
Perf
| where TimeGenerated > ago(60d)
| where ObjectName == "LogicalDisk" | where CounterName == "% Free Space"
| project CounterPath, TimeGenerated, InstanceName, CounterName, CounterValue
| summarize max(CounterValue) by bin(TimeGenerated, 12h), CounterPath
| render timechart with (title ="Virtual Machine Disk Usage", ymin=0, ymax=100)
Would appreciate if anyone as any clues, tips or tricks!
render is slightly different in Log Analytics to Azure Data Explorer (the docs are merged). You need to use range or make-series - would this example work for you?
Perf | where ObjectName == "LogicalDisk" | where CounterName == "% Free Space" | make-series pctDiskFreeSpace = max(CounterValue) default=0 on TimeGenerated in range(ago(60d), now(), 12h) by Computer | render timechart title ="Virtual Machine Disk Usage"Hey CliveWatson ,
That certainly sorts the Y axis range issue, thanks!
What I've lost using your code as is however is the spilt per instance name (machine/disk), it's now only showing one series per machine, rather than per disk. Pretty sure I can fix this with a bit of fooling around, I'll play with it through my day and let you know how I get on!Thanks
Its a busy chart but...this maybe?
Perf | where TimeGenerated > ago(60d) | where ObjectName == "LogicalDisk" | where CounterName == "% Free Space" | where InstanceName has ":" // just drive letters | make-series pctDiskFreeSpace = max(CounterValue) default=0 on TimeGenerated in range(ago(60d), now(), 12h) by CounterPath | render timechart title ="Virtual Machine Disk Usage"
