On Wed, Feb 2, 2011 at 9:35 PM, David Dabbs <dmda...@gmail.com> wrote: > We’re encountering some high read latency issues.
What is reporting high read latency? > We're more read than write, though there doesn't seem to be many pending > reads. > I have seen active/pending row-read at three or four, though. In general if you were I/O bound on reads (the most common pathological case) you would see much higher row-read stage pending. > [ sane looking tpstats ] Your tpstats does not look like a node which is struggling. > avg-cpu: %user %nice %system %iowait %steal %idle > 1.00 0.00 0.25 1.32 0.00 97.43 Your system also seems to not be breaking a sweat. > We're running on a beefy 64-bit Nehalem, so mmap should be > available/possible. > I need to check with our Cassandra lead when he's available as to why we're > not using mmap or auto. Probably because of : https://issues.apache.org/jira/browse/CASSANDRA-1214 > Heap size is 16gb. 16gb out of how much total? Do your GC logs seem to indicate reasonable GC performance? Do all nodes generally have a complete view of the ring and all nodes generally seem to be up? =Rob
