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HBase >> mail # user >> Handling regionserver crashes in production cluster


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Re: Handling regionserver crashes in production cluster
Yes we killed the region server but datanode is still running on the node...

Sample Test scenario: Assume, I have table with pre-splits a upto z (about
26 regions). I brought down region server purposefully with regions having
prefixes c and d. Then I used client API to scan data from regions with
prefixes other than c and d. The response was very slow and sometimes not
coming at all.

My doubt was if only regions with prefix c and d are getting relocated or
in transition. Why is it affecting the regions with other prefixes.... But
once the region transition is over, the response is very fast as expected.

On Wed, Jun 12, 2013 at 8:50 PM, rajesh babu chintaguntla <
[EMAIL PROTECTED]> wrote:

> You can configure below to more value to close more regions at a time.
>
>  <property>
>     <name>hbase.regionserver.executor.closeregion.threads</name>
>     <value>3</value>
>   </property>
>
>
> On Wed, Jun 12, 2013 at 7:38 PM, Nicolas Liochon <[EMAIL PROTECTED]>
> wrote:
>
> > What was your test exactly? You killed -9 a region server but kept the
> > datanode alive?
> > Could you detail the queries you were doing?
> >
> >
> > On Wed, Jun 12, 2013 at 2:10 PM, kiran <[EMAIL PROTECTED]>
> > wrote:
> >
> > > It is not possible for us to migrate to new version immediately.
> > >
> > > @Anoop we purposefully brought down one regionserver, then we observed
> > the
> > > website is taking too much time to respond. We observed the pattern for
> > > about 5 min till the regions are relocated.
> > > Also we issued queries in our website taking care that the queries did
> > n't
> > > come under the regions in the regionserver we brought down.
> > >
> > > Is there any configuration workaround to mitigate it??
> > >
> > > Thanks
> > > Kiran
> > >
> > >
> > >
> > > On Thu, Jun 6, 2013 at 8:27 PM, Jean-Marc Spaggiari <
> > > [EMAIL PROTECTED]
> > > > wrote:
> > >
> > > > Hi Kiran,
> > > >
> > > > Also, any chance for you to migrate to 0.94.8? There have been
> > > > hundreds of fixes since 0.94.1...
> > > >
> > > > JM
> > > >
> > > > 2013/6/6 Anoop John <[EMAIL PROTECTED]>:
> > > > > How many total RS in the cluster?  You mean u can not do any
> > operation
> > > on
> > > > > other regions in the live clusters?  It should not happen..  Is it
> so
> > > > > happening that the client ops are targetted at the regions which
> were
> > > in
> > > > > the dead RS( and in transition now)?   Can u have a closer look and
> > > see?
> > > > > If not pls check the RS threads were they are getting blocked.
> > > > >
> > > > > -Anoop-
> > > > >
> > > > > On Wed, Jun 5, 2013 at 10:50 PM, kiran <
> [EMAIL PROTECTED]>
> > > > wrote:
> > > > >
> > > > >> Dear All,
> > > > >>
> > > > >> We have production cluster that runs on hbase 0.94.1. The issue we
> > are
> > > > >> facing is whenever one regionserver goes down, the cluster becomes
> > > > >> unresponsive until all the regions are allocated to another
> > > > >> regionserver(s). The transition is taking about 3-5 mins and
> during
> > > this
> > > > >> time we are unable to any do client operation on the cluster.
> > > > >>
> > > > >> Is there any way we can make the transition to run in background ?
> > > > >>
> > > > >> Also, it is acceptable for us if the client operations such as
> scan
> > or
> > > > get
> > > > >> does not work on the rowkeys of regions in transition. But, they
> are
> > > not
> > > > >> working on the entire cluster until all the regions are moved out
> of
> > > > >> transition. We can't afford 3-5 minutes of downtime.
> > > > >>
> > > > >> --
> > > > >> Thank you
> > > > >> Kiran Sarvabhotla
> > > > >>
> > > > >> -----Even a correct decision is wrong when it is taken late
> > > > >>
> > > >
> > >
> > >
> > >
> > > --
> > > Thank you
> > > Kiran Sarvabhotla
> > >
> > > -----Even a correct decision is wrong when it is taken late
> > >
> >
>

--
Thank you
Kiran Sarvabhotla

-----Even a correct decision is wrong when it is taken late
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB