Two new storage engines for Varnish-Cache

Nils Goroll slink at
Mon Feb 6 07:12:44 UTC 2023

Celebrating the 17th anniversary of Varnish-Cache today, your Open-Source 
Varnish-Cache friends from UPLEX have just released an extension with two new 
storage engines (stevedores) and two basic storage routers (loadmasters).

The preferred public repository with support for issues, merge-requests and 
other activities is at


The buddy storage engine is an advanced, high performance stevedore with a fixed 
memory size based on a new buddy memory allocator implementation from first 

Its main advantages are that it only uses a fixed amount of memory and solves 
the LRU fairness issue in Varnish-Cache.


The fellow storage engine is an advanced, high performance, eventually 
persistent, always consistent implementation based on the same allocator as the 
buddy storage engine.

It eventually persists all objects on stable storage. Both raw devices and files 
are supported, but NVMe or other flash based storage with high random I/O 
throughput at low latency times is recommended as the underlying medium.


Two simple storage routers are provided by the module for now, round-robin and hash.

what else?

* slashmap is a curses interface to visualize allocations in real time

* Yes, we have statistics and counters. Not enough of them yet, though.

To read more:

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