* Balance shards for an index more evenly across multiple data paths
When a node has multiple data paths configured, and is assigned all of the
shards for a particular index, it's possible now that all shards will be
assigned to the same path (see #16763).
This change keeps the same behavior around determining the "best" path for a
shard based on space, however, it enforces limits for the number of shards on a
path for an index from the single-node perspective. For example:
Assume you had a node with 4 data paths, where `/path1` has a tremendously high
amount of disk space available compared to the other paths. If you create an
index with 5 primary shards, the previous behavior would be to assign all 5
shards to `/path1`.
This change would enforce a limit of 2 shards to each data path for that
particular node, so you would end up with the following distribution:
- `/path1` - 2 shards (because it has the most usable space)
- `/path2` - 1 shard
- `/path3` - 1 shard
- `/path4` - 1 shard
Note, however, that this limit is only enforced at the local node level for
simplicity in implementation, so if you had multiple nodes, the "limit" for the
node is still 2, so assuming you had enough nodes that there was only 2 shards
for this index assigned to this node, they would still both be assigned to
`/path1`.
* Switch from ObjectLongHashMap to regular HashMap
* Remove unneeded Files.isDirectory check
* Skip iterating directories when not necessary
* Add message to assert
* Implement different (better) ranking for node paths
This is the method we discussed
* Remove unused pathHasEnoughSpace method
* Use findFirst instead of .get(0);
* Update for master merge to fix compilation
Settings.putArray -> Settings.putList
78c54c4560