Hi,

My scenario is...
Class B sub-net - 172.20.x.x /16
Multiple Virtual servers running on Microsoft HyperV 2012R2 host.
All Servers are backed up at night to NAS located in different building on a different switch - 172.20.99.247

Problem: All virtual servers are unresponsive during the backup window leading to Failover Cluster problems.

The 2 attached screen shots are the ping plots between 2 servers during the backup window.
Fig 1. during backup
Fig 2. backup disabled and NAS disconnected.

I am pretty sure it is a bandwidth issue, sending all that data across a 1Gbps Fibre link but I am struggling to interpret fig 1. - Why do other servers and switch appear as hops when packet loss occurs, especially when the 2 servers I am pinging are connected to the same switch ??

Thanks,
Graham

Obviously not got the hang of this.
The image displayed is Fig2.
Fig1. is the downloadable image.

Thanks
Graham

Hey Graham,

You've *definitely* got some pretty interesting looking results here - thanks for sharing these screenshots!

Judging from the looks of the timeline graph in "Fig 1." - I'd say that your inclination that this is a bandwidth issue seems to be on the right track.

The other servers and the switch showing up as hops in your route *is* a bit confusing to us as well, though (these kind of results aren't common at all). It could be that the switch is is attempting to route the packets that PingPlotter is sending out through other devices in the cluster (in an attempt to deal with any unresponsiveness/failures), but it's tough to tell for certain.

If you'd like, feel free to send over a pp2 file (or use the "File" -> "Share" option in PIngPlotter and shoot over the link) - as we'd love to take a closer look at this data! Or you can email us at support@pingman.com as well.

Best wishes,

-Gary

Hi Gary,

Thanks for replying. This had certainly baffled us. So much so we went to site last night to see for ourselves what was happening during the backup window.
To cut a long story short we discovered that the 5 x 48 port switch fabric that is connected via the cascaded ports had 3 ports in switch #1 patched directly to 3 ports in switch #2 and Spanning Tree was disabled.
I guess this would explain why other devices appeared in the graph.
I will email you the workspace file prior to our visit.

Many Thanks
Graham