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From Norbert Burger <norbert.bur...@gmail.com>
Subject Re: 答复: one table flushes at much smaller sizes than other?
Date Fri, 27 Dec 2013 04:35:33 GMT
Thanks Ted and Liang.  I do see the "Too may hlogs" line in our logs.

We're using the default values for hbase.regionserver.maxlogs = 32 and
hbase.regionserver.hlog.blocksize = 64MB, so

So given a heapsize = 12GB and lowerLimit = 0.35, does it make sense that I
should raise maxlogs to be something like 64 or 72?

Norbert



On Thu, Dec 26, 2013 at 11:03 PM, Ted Yu <yuzhihong@gmail.com> wrote:

> Norbert:
> What's your setting for hbase.regionserver.maxlogs ?
>
> Cheers
>
> On Dec 26, 2013, at 7:51 PM, 谢良 <xieliang@xiaomi.com> wrote:
>
> > Do you observe some log like "Too many hlogs" before flushing a few
> > dozen KB log ?  Just want to double-check it's weather a forcing flush
> issue
> > or not:)
> >
> > Thanks,
> > Liang
> > ________________________________________
> > 发件人: Norbert Burger [norbert.burger@gmail.com]
> > 发送时间: 2013年12月27日 5:52
> > 收件人: user@hbase.apache.org
> > 主题: one table flushes at much smaller sizes than other?
> >
> > Hi folks, we're currently running CDH4.1.2 (HBase 0.92 + patches).
> >
> > Looking through the logs, I'm seeing that some tables are flushing at
> much
> > lower size than others (a few dozen KB as opposed to the expected 128
> MB).
> >
> > Looking through some of great case studies like [1], [2], and [3], it's
> not
> > clear to me why this is happening.  We're using the defaults for upper,
> > lower limits (0.35 and 0.40, respectively), and the RS status pages show
> > that we're only using 25% of our memstore allocation.
> >
> > Our regions/RS ratio is currently at 60-70.  We do have some other tables
> > online where column families are skewed heavily sizewise -- could this be
> > causing other tables in our cluster to flush more frequently than others?
> >
> > Norbert
> >
> > [1]
> http://blog.sematext.com/2012/07/16/hbase-memstore-what-you-should-know/
> > [2] http://www.ngdata.com/visualizing-hbase-flushes-and-compactions/
> > [3] http://gbif.blogspot.com/2012/07/optimizing-writes-in-hbase.html
>

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