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From Matthew LeMieux <...@mlogiciels.com>
Subject Re: Slow Inserts on EC2 Cluster
Date Wed, 01 Sep 2010 14:24:39 GMT
I'm starting to find that EC2 is not reliable enough to support HBase.  I'm running into 2
things that might be related: 

1) On idle machines that are apparently doing nothing (reports of <3% CPU utilization,
no I/O wait)  the load is reported as being higher than the number of cores.   I don't know
if attachments work on the mailing list, but I attached a small image anyway to illustrate
this confusing thing.  (I've been using m1.large and m2.xlarge running CDH3)

2) Every once in a while it seems that somebody hits the pause button on one of my instances,
and while the CPU utilization stays low, the load value spikes to a high value.  When this
happens the region servers decide to close up shop.  It appears to be a problem with contacting
zookeeper servers (who happen to stay up and running, but perhaps somewhat unresponsive when
Amazon decides to hit the pause button).  I have extended the timeout for contacting zookeeper
servers, but these events continue to persist.  One such event happened 8 hours ago, and I
still can't get HBase back up and running. 

I've seen many comments on this list informing users that they are using hardware (or virtual
machines) that are simply not big enough, not fast enough, or don't have enough memory.  I'd
like to offer an alternative point of view.  Whether or not EC2 will last is uncertain, but
cloud computing environments will definitely be around for a long time.  What would it take
to make HBase resilient enough to take advantage of those environments?  Based on my experience
and comments on this list, it seems "HBase in the cloud" is still a rather painful proposition.


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