wrkdsksts activity pct. was: disk arms (was RE: Tips for user ASP)

What with the disk controllers having cache memory, does anyone know if the
WRKDSKSTS percentages reflect cache activity or actual disk arm activity ?

The implication being that a cache that is 10% busy or 90% busy is
inconsequential since it is all instant memory access, without any wait
needed. ( especially when writing to the cache )

The activity number that will give meaningful info is activity on the back
end of the cache, where the disk arms put and get to the cache.  For
example, how frequently is the cache full so that the next write to the
cache must wait for cache data to be written to disk.  And how frequently do
reads from the disk cache not find the data being sought in the cache,
resulting in a wait for an actual disk read to be completed.

Steve Richter