Mapping VSAN components

Recently I had been asked to look at some performance issues on a bunch of VMs which were showing increased write latency. But how do you know where the VM is sending it’s I/O in such a distributed system? With VSAN the compute resource for a VM could be on one server where all I/O […]

CPU Spikes when calling a SCSI INQUIRY

We were seeing some spike in CPU usage every 15 minutes on some new servers. As these systems were idle i.e. no workload apart from the operating system this makes an investigation slightly easier as we don’t have any application workloads to add to the mix. Below we can see an example of the spikes […]

Building a dynamic QOS with eBPF and Cgroups

In my previous posts I have shown how the SolidFire Array QOS  implements QOS on a per volume basis. As I was looking for a new project I asked myself could I write a similar QOS program which runs on a virtual machine? I wondered could I dynamically change the Linux built-in QOS(throttling) which is […]