bbf9ce18ef
Currently, the tablet load balancer performs capacity based balancing by collecting the gross disk capacity of the nodes, and computes balance assuming that all tablet sizes are the same. This change introduces size-based load balancing. The load balancer does not assume identical tablet sizes any more, and computes load based on actual tablet sizes. The size-based load balancer computes the difference between the most and least loaded nodes in the balancing set (nodes in DC, or nodes in a rack in case of `rf-rack-valid-keyspaces`) and stops further balancing if this difference is bellow the config option `size_based_balance_threshold_percentage`. This config option does not apply to the absolute load, but instead to the percentage of how much the most loaded node is more loaded than the least loaded node: `delta = (most_loaded - least_loaded) / most_loaded` If this delta is smaller then the config threshold, the balancer will consider the nodes balanced. This PR is a part of a series of PRs which are based on top of each other. - First part for tablet size collection via load_stats: #26035 - Second part reconcile load_stats: #26152 - The third part for load_sketch changes: #26153 - The fourth part which performs tablet load balancing based on tablet size: #26254 - The fifth part changes the load balancing simulator: #26438 This is a new feature, backport is not needed. Fixes #26254 Closes scylladb/scylladb#26254 * github.com:scylladb/scylladb: test, load balancing: add test for table balance load_balancer: add cluster feature for size based balancing load_balancer: implement size-based load balancing config: add size based load balancing config params load_stats: use trinfo to decide how to reconcile tablet size load_sketch: use tablet sizes in load computation load_stats: add get_tablet_size_in_transition()
Scylla in-source tests.
For details on how to run the tests, see docs/dev/testing.md
Shared C++ utils, libraries are in lib/, for Python - pylib/
alternator - Python tests which connect to a single server and use the DynamoDB API unit, boost, raft - unit tests in C++ cqlpy - Python tests which connect to a single server and use CQL topology* - tests that set up clusters and add/remove nodes cql - approval tests that use CQL and pre-recorded output rest_api - tests for Scylla REST API Port 9000 scylla-gdb - tests for scylla-gdb.py helper script nodetool - tests for C++ implementation of nodetool
If you can use an existing folder, consider adding your test to it. New folders should be used for new large categories/subsystems, or when the test environment is significantly different from some existing suite, e.g. you plan to start scylladb with different configuration, and you intend to add many tests and would like them to reuse an existing Scylla cluster (clusters can be reused for tests within the same folder).
To add a new folder, create a new directory, and then
copy & edit its suite.ini.