-tserver.readahead.concurrent.max set to 64 but only running 32 at most.
When tserver.readahead.concurrent.max was set to its default setting, the
load on our tservers was fairly low. So I changed accumulo-site.xml so the
max is 64. (Go for the gusto!) Then restarted the tservers to ensure the
change was picked up.
New queries are now running 32 concurrent scans on each server with several
scans waiting in the queue. Is there some other accumulo parameter that I
need to set to get more than 32 concurrent scans? Is something else
affecting the scans?