Observe about 50% iowait before even starting clients - that is when
there is actually no load from clients on the system. So only "internal"
stuff in HBase/HDFS can cause this - HBase compaction? HDFS?
Regards, Per Steffensen
Per Steffensen skrev:
Hi
We have a system a.o. with a HBase cluster and a HDFS cluster
(primarily for HBase persistence). Depending on the environment we
have between 3 and 8 machine running a HBase RegionServer and a HDFS
DataNode. OS is Ubuntu 10.04. On those machine we see very high iowait
and very little "real usage" of the CPU, and unexpected low throughput
(HBase creates, updates, reads and short scans). We do not get more
throughput by putting more parallel load from the HBase clients on the
HBase servers, so it is a "real" iowait problem. Any idea what might
be wrong, and what we can do to improve throughput and lower iowait.
Regards, Per Steffensen
