How Elasticsearch Handles Deletions (and Why Our 30TB Purge Didn’t Break Anything)

I recently joined a new team & my onboarding task was to optimize storage in one of our Elasticsearch clusters which held 100s of terabytes of data. One of the first things we needed to figure out was whether the system could survive a massive deletion during peak traffic. We expected indexing to clog up and search latencies to spike. What actually happened was more interesting: the cluster…