Open Source5 min read
Apache Flink 1.4+ · BLOB storage internals
Apache Flink's blob store holds unused blobs 30 minutes before cleanup
Flink's BLOB rewrite added checksum verification, reference counting and a layered store split between a central server and per-TaskManager caches. It trades disk space for safety by holding dead blobs before cleanup, with the retention interval now at 30 minutes.
2026-09-14