Cephalocon 2019

CephFS is a powerful file system, but sometimes the performance metrics and error messages developers talk about are abstract and obscure. This talk will illuminate CephFS file capabilities: how they are thoroughly different from the unfortunately-similarly-named CephX caps, their purpose and utility, and why they are a critical performance and correctness issue. Understand the warning messages you may see about clients holding on to them and failing to drop caches and how to read their output. Finally, get a brief lesson in how to program with caps when working in Ceph’s client libraries!