diff --git a/Documentation/About/Limitations.md b/Documentation/About/Limitations.md index 53e7918db..f56c5a156 100644 --- a/Documentation/About/Limitations.md +++ b/Documentation/About/Limitations.md @@ -4,6 +4,8 @@ This document lists known issues and limitations in MariaDB MaxScale and its plugins. Since limitations are related to specific plugins, this document is divided into several sections. +[TOC] + ## Configuration limitations In versions 2.1.2 and earlier, the configuration files are limited to 1024 @@ -14,6 +16,16 @@ In versions 2.2.12 and earlier, the section names in the configuration files were limited to 49 characters. This limitation was increased to 1023 characters in MaxScale 2.2.13. +### Multiple MaxScales on same server + +Starting with MaxScale 2.4.0, on systems with Linux kernels 3.9 or newer due to +the addition of SO_REUSEPORT support, it is possible for multiple MaxScale +instances to listen on the same network port if the directories used by both +instances are completely separate and there are no conflicts which can cause +unexpected splitting of connections. This will only happen if users explicitly +tell MaxScale to ignore the default directories and will not happen in normal +use. + ## Security limitiations ### MariaDB 10.2 diff --git a/Documentation/Release-Notes/MaxScale-2.4.0-Release-Notes.md b/Documentation/Release-Notes/MaxScale-2.4.0-Release-Notes.md index 2d31eca90..65b1fa0b3 100644 --- a/Documentation/Release-Notes/MaxScale-2.4.0-Release-Notes.md +++ b/Documentation/Release-Notes/MaxScale-2.4.0-Release-Notes.md @@ -19,6 +19,19 @@ configuration files, then MaxScale will not start. Whitespace in section names that was deprecated in 2.2 will now be rejected and cause the startup of MaxScale to fail. +### Binding on network ports + +MaxScale 2.4.0 will now use the SO_REUSEPORT capability offered by newer kernels +that allows reuse of network listener ports. In practice this means improved +connection creation speed with more dynamic balancing of connections. + +As a side-effect of this, it is possible for two MaxScale instances to bind on +the same listener port on systems that have Linux kernels newer than 3.9. This +can only happen if the MaxScale instances use completely different directory +structures (i.e. different `--basedir` arguments). Normal use of MaxScale still +detects multiple MaxScales trying to bind to the same ports. Almost always, this +will not have any negative side-effects. + ## Dropped Features ## New Features