CDS Pacific highlights - RADOS

Hi everyone, A couple of weeks ago the first online Ceph Developer Summit was held to plan and discuss features for the next Ceph release - Pacific. Here are some of the highlights from the RADOS session. Recording: https://www.youtube.com/watch?reload=9&v=4KZCB-XzFCY General improvements - Adaptive recovery settings for smarter throttling of client vs recovery I/O - Reflect severity of degradedness in ceph health and improve mechanism to discover unfound objects that can help recover PGs - Distributed tracing in the OSD I/O path to identify performance bottlenecks and improve debugging capabilities - https://github.com/ceph/ceph/pull/31358 - Telemetry: mapping device errors and osd crashes back to devices to help improve disk prediction models - New score-based leader election system in the monitors - first step to reliable stretched Ceph clusters - https://github.com/ceph/ceph/pull/32336 - Controlled osdmap trimming - https://github.com/ceph/ceph/pull/19076 - Automated OSD re-provisioning by the manager to help with repair and migrating to new BlueStore formats - Dedup support starting with RGW - https://github.com/athanatos/ceph/blob/sjust/wip-refcount/doc/dev/deduplica… - Manager and python subinterpreters - leave subinterpreters as they are now, evaluate the need to return to a single interpreter and review mgr modules for problematic dependencies BlueStore and Performance related improvements - Lower Write Amplification and improve space-amplification with rocksdb column family sharding - https://github.com/ceph/ceph/pull/34006 - Lower Space Amplification - New hybrid allocator - https://github.com/ceph/ceph/pull/33365 - Deferred "big" writes - https://github.com/ceph/ceph/pull/33434 - Memory Management - Onode double cache fix - https://github.com/ceph/ceph/pull/27705 - Cache age-based binning - https://github.com/ceph/ceph/pull/23710 - Onode data structure diet - https://github.com/ceph/ceph/pull/32697 - Fix onode cache pinning - https://github.com/ceph/ceph/pull/32852 - io_uring - Code is already in ceph, io_uring kernel support backported to centos 8.2. - Consider making it default for kernels that support it - Should we continue to depend on the current aio_t for io_uring? - Ongoing QoS work - Balancer and PG autoscaler - Turn balancer on in upmap mode by default and set min_compat_client to luminous for new clusters - https://github.com/ceph/ceph/pull/34541 - Smarter balancing of PGs - take into account bytes used, omap used to balance in addition to pg_num, balance based on primariness for read performance - PG autoscaler only scale down under pressure More details in: https://pad.ceph.com/p/cds-pacific https://trello.com/b/ugTc2QFH/ceph-backlog (look for the blue pacific label) Thanks, Core RADOS Team