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Case Study - Data Distribution

· 6 min read

Happened Before

After the initial production success of tremor as a point solution for capacity management during our peak trading cycles at Wayfair, the focus shifted a little to the next key set of issues with our traditional observability platforms.

The simplified architecture of our logging systems is currently:

old pipeline

The traffic shaping use case was a huge win for Wayfair's SRE and operational teams who manage our production estate.

Identified Need

But we could do a lot better. The development lifecycle to capture, normalize, enrich, enhance and standardize logs from 1000's of engineers, 1000's of applications built in a diversity of programming languages was a have task for our observability engineers.

Their environment still looks pretty grim:

new pipeline

Displace and replace a plethora of in-house, open-source and commercial off the shelf log capture, metrics capture and data distribution technologies with a single cost-effective at hyperscale dynamically load-adaptive solution.

The decision was taken to expand the processing capabilities of tremor beyond traffic shaping, classification and rate limiting rules to general purpose data processing of unstructured hierarchic JSON-like data streams. The shape of data most common within the observability domain we were focused upon.

Required Outcome

Our systems specialists and service reliability engineers can consolidate knowledge and tune to a unified operating experience and center of excellence in our production estate based on a single well known and cost efficient easy to operate alternative.


It is understood that data will be captured from and distributed to a diverse and ever-changing set of production systems - built in many programming languages and environments and distributed to an unknowable set of destination systems.

These systems include, but are not limited to: Graylog Extended Log Format, Syslog,
Kafka, TCP, UDP, Telegraf, Influx Line Protocol, ElasticSearch and many more...

Connectivity must be flexible enough to capture data from and distributed data to synchronous, asynchronous protocols, transports and systems without developers needing to learn or integrate with a new technology. The solution must be invisible to developers.

The unit economics of the existing system is hard to measure, hard to plan and hard to remediate; especially given the rising year on year firehose volumetrics, with rising velocity and rising peak loads.

99% of the data either originates as JSON, or is transformed to JSON just in time.

The target systems for displacement and replacement have very well understood and extract, load, transform, enrichment and normalization algorithms that are coded and configured differently in each system. This is difficult to maintain, enhance and evolve in an environment where infrastructure and services are continuously evolving.

A rich set of ETL and data manipulation and mutation primitives are required so that all existing methods used for data processing across the target systems can be replaced by a single easy to understand, easy to program and optimized alternative.


Tremor has already established itself in the traffic shaping domain in the logging and metrics domains - adding just-in-time traffic shaping capabilities when needed; and preserving the original system’s operational semantics and behaviours during normal operating conditions when the system is operating within planned capacity constraints.

new pipeline

The mandate now expands to replacing many of our event capture systems deployed on on-premise and cloud-native operating environments across multiple data-centres globally.

Instead of our operations and service reliability teams needing to learn and manage the service deployment and administrative lifecycle of multiple components in this evolution we displace and replace those systems - typically operating as sidecars on source systems where our applications run on virtual machines, bare metal or containerized environments with tremor.

The relatively primitive domain specific language developed as part of the initial solution for traffic shaping is replaced with a new domain specific language tremor-script designed for expressive data filtration, extraction, enrichment and transformation to support:

  • Classification, Categorization and rate limiting for Traffic Shaping
  • Enrichment, Normalization and micro-format parsing
  • Structural pattern matching over hierarchical nested JSON-like data
  • The ability to patch, merge and iterate over JSON-like data
  • A familiar expression language like in regular programming languages with arithmetic, multiplicative and other common operations on numeric and string data
  • Testing string encoded data for regular expression and other micro-formats such as the logstash grok, dissect, kv or stringified embedded json

The resulting language and interpreter for tremor-script forms the basis of the solution and is largely designed around the needs of the logging domain - but delivered in a more generally useful incarnation that is more widely applicable to other domains - such as in flight data analytics, in flight ETL or processing metrics to name a few.

Most of the in-flight events are JSON or JSON-like. Inspired by a tweet the tremor team happens upon the work of Daniel Lemire et al and SIMD-accelerated JSON processing. Heinz ports this to rust and tremor’s sister project and organization simd-lite is born. The tremor team also maintains the rust port of simd-json with other maintainers interested in fast and efficient data parallel parsing of JSON.

Finally, tremor undergoes a steady pace of innovation with benchmark driven performance optimizations. The combined effect of an efficient interpreter, the ability to easily benchmark synthetic analogs of real world use cases in our benchmark system, and the adoption of more workload appropriate and efficient low level memory allocators such as jemalloc, then mimalloc, then snmalloc by Microsoft Research results an order of magnitude level of infrastructure cost savings. The production estate shrinks by 10x in terms of the number of deployed systems, the compute capacity required, and the committed memory required when compared to the displaced and replaced systems.

Further - tremor uses far less memory and resources on the source systems making it a much improved sidecar on our source hosts.


Tremor’s core mission and mandate now extends from high quality of service data distribution with load-adaptive traffic management for the 1% ( and typically less ) of time our systems are under-resourced; and, the other 99% of the time is 10x more cost efficient.

Tremor preserves its facility to remain invisible to developers during this phase of expansion whilst drastically improving the lives of our operational engineers and service reliability engineers. The measured and validated cost-efficiencies offer compounding value that further drives the mandate of the project and pushes it into its next phase of evolution.