Just in time configuration cuts memory usage and speeds up restart time by cutting down on the number of Apache vhosts LSWS has configure at server startup.
We’ve seen customers with over 30,000 virtual hosts on one box or one cluster with shared storage. For these users, restarting can take minutes. Our graceful restarting means that these restarts cause zero downtime, but they’re a resource drag and make it hard to maintain a server. With just in time configuration, instead of parsing all Apache virtual host configurations at startup, the web server parses virtual host configurations the first time the vhost’s site is accessed. This means that inactive vhosts are left alone until they are requested, cutting memory usage and leading to a faster startup/restart. You should really start to see the difference on servers with lots of virtual hosts — for example, a shared hosting server with more than 500 users.
The Just In Time Configuration setting is located in the WebAdmin console > Configuration > General > Using Apache Configuration File. Turning it on applies just in time configuration to all virtual hosts in Apache configuration files. LiteSpeed-native virtual hosts are unaffected.
Stay tuned this afternoon for an explanation of the new PHP suEXEC WorkerGroup mode and how it allows even more efficient opcode caching. Making the jump!