HBASE-22301 for logic that requests to roll the WAL if regionserver encounters a slow write pipeline. In the logs, during regionserver start, I see that the WAL is requested to roll once. It's strange that we roll the WAL because it wasn't a slow sync. It appears when this code executes, we haven't initialized the rollOnSyncNs variable to use for determining whether it's a slow sync. Current pipeline also shows empty in the logs.
Disclaimer: I'm experiencing this after backporting this to 1.3.x and building it there - I haven't attempted in 1.5.x, though I'd expect similar results.
Regionserver logs follow (notice threshold=0 ms, current pipeline: ):