commit interval
also: dirty_writeback_centisecs, journal commit timeout
The maximum time the kernel waits before flushing dirty (modified) filesystem data to disk, typically 5 seconds by default. This balances performance with data safety.
A commit interval is a kernel tuning parameter that controls how long the filesystem can hold modified data in memory before forcing a write to persistent storage. The default is usually 5 seconds, meaning the kernel will not let more than 5 seconds pass without syncing dirty pages to disk.
This is a trade-off between performance and reliability. Longer intervals (e.g., 30 seconds) improve performance by batching writes but increase data loss risk if the system crashes. Shorter intervals (e.g., 1 second) provide safer writes but may reduce throughput.
You can view and modify the commit interval on ext4 filesystems using tune2fs -l /dev/sda1 | grep commit or adjust it via mount -o commit=10 /dev/sda1 to set a 10-second interval.