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From Kirill Shabunov <e2...@yahoo.com>
Subject Re: HBase looses regions.
Date Mon, 25 May 2009 19:58:17 GMT
Thanks a lot for the advice!

What should I do to vote for the release? I just subscribed for 
hbase-dev list.

--Kirill

stack wrote:
> On Fri, May 22, 2009 at 7:21 AM, Kirill Shabunov <e2k_1@yahoo.com> wrote:
> 
>> Thanks a lot!
>>
>> I've tried, it seems to be much more stable overall. No component have
>> crashed so far.
> 
> 
> I'm glad.   If the RC is working for you, please vote for it over in
> hbase-dev mailing list.
> 
> 
>>
>> I see some new messages, like this:
>>  WARN org.apache.hadoop.hbase.regionserver.HLog:
>> regionserver/0:0:0:0:0:0:0:0:60020.logFlusher took 1661ms optional sync to
>> HLog; editcount=0
>>
> 
> This is a new log I added.  It triggers every time an append or a "sync" on
> the commit log takes > 1 second.  I added the log to highlight hdfs slow
> periods taking on writes.  Its looking like we are going to have to put up a
> pool of commit log writers if we want to keep up write rates.  The logging
> is just so we begin to gather stats.
> 
> In the above, it looks like it happened just after file open (editcount=0).
> 
> 
> I also changed some settings:
>> 1. upped hbase.master.lease.period to allow regions to be busy longer.
>>
> 
> 
> Thats probably fine.
> 
> 
> 
>> 2. decreased some thresholds, where I hope it should reduce RAM usage:
>>    - hbase.hregion.memcache.flush.size -- smaller buffers (?).
>>    - hbase.hregion.max.filesize -- smaller the region, less RAM for the
>> index (?).
>>
> 
> 
> Regards memory use, I would have left the above settings at default.  In
> 0.19.x era hbase, its the size of your storefile indices that takes up bulk
> of heap.  See http://wiki.apache.org/hadoop/Hbase/FAQ#4.  This should all be
> much better in 0.20.0 hbase.
> 
> St.Ack
> 

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