what does Average percentage of local files to RegionServer mean?

[#1]

I found the metric Regionserver.Server.percentFilesLocal on ambari which is showing 20%. What is the meaning of the metric? Any details would be appreciated.

[#2 · Accepted solution]

That's the ratio of HFiles associated with regions served by an RS having one replica stored on the local Data Node in HDFS. RS can access local files directly from a local disk if short-circuit is enabled. And If you, for example run a RS on a machine without DN, its locality will be zero. You can find more details here. And on HBase Web UI page you can find locality per table.