Rework `shell.EcBalance()`'s waitgroup with errors code into a standalone type.
We'll re-use this for other EC jobs - for example, volume creation. Also fixes
potential concurrency issues when collecting error results.
* Begin implementing EC balancing parallelization support.
Impacts both `ec.encode` and `ec.balance`,
* Nit: improve type naming.
* Make the goroutine workgroup handler for `EcBalance()` a bit smarter/error-proof.
* Nit: unify naming for `ecBalancer` wait group methods with the rest of the module.
* Fix concurrency bug.
* Fix whitespace after Gitlab automerge.
* Delete stray TODO.
* Account for replication placement settings when balancing EC shards within racks.
* Update help contents for `ec.balance`.
* Add a few more representative test cases for `pickEcNodeToBalanceShardsInto()`.
* Improve EC shards rebalancing logic across nodes.
- Favor target nodes with less preexisting shards, to ensure a fair distribution.
- Randomize selection when multiple possible target nodes are available.
- Add logic to account for replication settings when selecting target nodes (currently disabled).
* Fix minor test typo.
* Clarify internal error messages for `pickEcNodeToBalanceShardsInto()`.
Improve EC shards rebalancing logic across racks.
- Favor target shards with less preexisting shards, to ensure a fair distribution.
- Randomize selection when multiple possible target shards are available.
- Add logic to account for replication settings when selecting target shards (currently disabled).
* Rename `command_ec_encode_test.go` to `command_ec_common_test.go`.
All tests defined in this file are now for `command_ec_common.go`.
* Minor code cleanups.
- Fix broken `ec.balance` test.
- Rework integer ceiling division to not use floats, which can introduce precision errors.
* Introduce logic to resolve volume replica placement within EC rebalancing.
This will be used to make rebalancing logic topology-aware.
* Give shell.EcNode.dc a dedicated DataCenterId type.
* Refactor `ec.balance` logic into a `weeed/shell/command_ec_common.go` standalone function.
This is a prerequisite to unify the balance logic for `ec.balance` and `ec.encode'.
* s/Balance()/EcBalance()/g
Lisandro Pin