Network Monitoring Issue

Hello all, I’m new here to the forum but have been watching the L1 vids for awhile. I wasn’t sure where to actually put this question, so feel free to move it to the correct section.

We are using PRTG NetMon at my current job. I am currently tasked with getting it working efficiently and correctly, apparently the previous Admin just kinda installed it, setup a few things and kept paying the yearly fees, but never did much with it.

There are some Disk sensors that are returning high values for the Write Latency Max fields on the HDD’s on several servers. As in 17,722ms in some cases. I know that is WAY out of spec of what we should be expecting.

Can someone tell me what this actually means and is it concerning? I have looked at PRTG’s information and it’s just very direct to the point, without actually explaining WHY the values are high.

I can tell you we are running VCenter 6.7, using datastores on an Intelliflash storage system. There are about 4 or 5 VM’s that are reporting this same latency issue and I know they are on the same datastore. The Intelliflash doesn’t report any issues with the drives.

Thanks for helping if you can,
Paul

Maybe start with moving one the problem VM’s over to another datastore. Just to see if problem persists on another datastore.
If VM seems ok…move another problem VM to same store.

(example:I have seen SQL servers and Exchange servers bringing down a data store and getting those type of latency errors…also those products may report those problems too in the eventlog of the machine itsself)

Your disk values are likely high because your company has made the classic mistake of running way too many VMs on not enough spindles because they had disk space for it.

You’ll run out of speed long before you run out of space with disk in a vm environment usually.

To be fair the tools for tracking disk IO problems in vSphere are fucking trash unless you pay for ops manager, and even then trying to authoritatively tell management they need to spend a heap on more drives not bigger ones is hard.