OMS Logical disk performance counters not existing disk instancename

Question

We use Azure OMS to monitor many of our on premise servers.

When using the LogicalDisk(*)\% Free Space performance counter there are some non existing instanceNames for example HarddiskVolume170, HarddiskVolume89, ...

When checking perfmon on the Server I see 3 logical disk instances for the free space performance counter.

1. C:
2. HarddiskVolume1
3. _Total

When checking the OMS logs there clearly are some other instances. If you check the count they were active for a limited amount of time.

What are these other instance names ? Are these temporary logical disks that get spawned ? I would like to figure out these instances are.

Thx in advance !

Answer 1

It seems some tools/software creates temporary virtual disks for example the Azure backup agent. These info disks are added to the performance counters logs and transfered to log analytics.

We did not really have a solution for this. But its clear in our alert that its an temporary/virtual instance drive and can be ignored.