Vector is described as 'open source on-host performance monitoring framework which exposes hand picked high resolution system and application metrics to every engineer’s browser' and is an app in the System & Hardware category. There are six alternatives to Vector for a variety of platforms, including Linux, Mac, Windows, BSD and Self-Hosted solutions. The best alternative is Prometheus, which is both free and Open Source. Other great apps like Vector are Graphite (Free, Open Source), Loki (Free, Open Source), Axibase Time Series Database (Free) and DalmatinerDB (Free, Open Source).
Prometheus is an open-source systems monitoring and alerting toolkit originally built at SoundCloud. Since its inception in 2012, many companies and organizations have adopted Prometheus, and the project has a very active developer and user community.
Loki is a horizontally-scalable, highly-available, multi-tenant log aggregation system inspired by Prometheus. It is designed to be very cost effective and easy to operate. It does not index the contents of the logs, but rather a set of labels for each log stream.
ATSD is purpose-built for analyzing and reporting on massive volumes of time-series data collected at high frequency. Features include data analytics, visualization, data forecasting, reporting, alerting. All in one product built for big data.
DalmatinerDB is a metric database written in Erlang. It takes advantage of special properties of metrics to make trade-offs. The goal is to make a store for metric data (time, values) that is fast, has a low overhead, and is easy to query and manage.