Massive Storage Engine 4 - General availability information Announcement

Published June 20, 2024.


Massive Storage Engine 4 (MSE4) is the fourth generation in the series and was made generally available earlier this month. MSE is a stevedore, which is the component in Varnish that manages how and where cached data are stored. MSE can be used for ephemeral caching (in DRAM, called “memory-only”) and persistent caching (typically in SSDs). It is shipped with Varnish Enterprise.

This post aims to share some information about the current status of MSE4 and plans for the first weeks and months of its general availability period.

Current status

After extensive planning and two years of development, MSE4 was recently made generally available for all Varnish Enterprise users. The modular architecture in Varnish allows the new code to be active only when MSE4 has been enabled, which eliminates the risk of introducing issues to existing environments.

Initial phase of General Availability

We have done synthetic testing in the lab, but we still expect some issues to appear once early adopters deploy it to their production environments. We will work on analyzing and fixing these issues as they are discovered and reported.

During this initial phase, we expect to have a higher rate of fixes and improvements than normal. We will try to keep the number of releases to a minimum, by accumulating fixes between the releases. The early adopters than require access to the latest but not yet released fixes can get access to a separate repository that contains the release candidate of the next version of Varnish Enterprise. Please reach out to to get access to this repository.

The initial phase will last until MSE4 has been properly exposed to various workloads over time, with good results. Once this has been completed, we will announce it here and flag it as a milestone. We expect this to take a few months.