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From lars hofhansl <la...@apache.org>
Subject Re: RegionServer - Insufficient Memory and Cascading Errors
Date Mon, 09 Mar 2015 17:53:04 GMT
Sub 1GB heaps are not useful for anything but cursory functional testing with a few rows. It
does not give the GC enough leeway to deal with the per RPC garbage that HBase produces.
But this does not translate to similar behavior with more data and larger heaps.

If I can plug my own blog post here...

Here's a note I wrote I about GC tuning for HBase: http://hadoop-hbase.blogspot.com/2014/03/hbase-gc-tuning-observations.html
And here's on region server sizing: http://hadoop-hbase.blogspot.com/2013/01/hbase-region-server-memory-sizing.html
-- Lars

From: Mark Tse <Mark.Tse@D2L.com>
To: "user@hbase.apache.org" <user@hbase.apache.org> 
Sent: Friday, March 6, 2015 12:20 PM
Subject: RegionServer - Insufficient Memory and Cascading Errors

Hi everyone,

When I do a scan on a table with about 700 rows (about 50 columns each), the RegionServers
will systematically go offline one at a time until all the RegionServers are offline. This
is probably due to there not being enough memory available for the RegionServer processes
(we are working with sub-1G for our max heap size on our test clusters atm).

Increasing the max heap size for the RegionServers alleviates this problem. However, my concern
is that this kind of cascading failure occurs on production with large datasets even with
a larger heap size.

What steps can I take to prevent this kind of cascading error? Is there a way to configure
RegionServers to return an error instead of just failing (and causing HBase Master to hand
the task to the next available RegionServer)?


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