Per Steffensen skrev:
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?
Ahh ok, that was only for half a minute after restart. So basically down
to 100% idle when no load from clients.
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
