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HBase >> mail # user >> Region servers going down under heavy write load


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Re: Region servers going down under heavy write load
Thanks for the pointer to HBase book.

I should have provided more background in my last email.

There is only one place in http://hbase.apache.org/book.html where
'hbase.zookeeper.property.tickTime' is mentioned - see bottom of the email.

There was no mentioning of HBASE_MANAGES_ZK variable in the vicinity of
this text. Some users would assume that the two referenced config
parameters, once set in hbase-site.xml, would be effective for future
zookeeper session timeout. However, if the zookeeper quorum is shared
across multiple HBase clusters, user's expectation wouldn't be met.

This is because zookeeper currently doesn't support different tickTimes for
different clusters. Without properly setting tickTime, the requested
session timeout wouldn't be satisfied.
There is a second, minor, issue with the text below. 1200000, in
milliseconds, represents 20 minutes instead of the declared 120 seconds.

Considering the above two points, I suggested using a JIRA to refine
src/docbkx/troubleshooting.xml.

Is that Okay ?

Here is text from 12.9.2.7. 'ZooKeeper SessionExpired events' of the HBase
book:

If you wish to increase the session timeout, add the following to your
hbase-site.xml to increase the timeout from the default of 60 seconds to
120 seconds.

<property>
    <name>zookeeper.session.timeout</name>
    <value>1200000</value>
</property>
<property>
    <name>hbase.zookeeper.property.tickTime</name>
    <value>6000</value>
</property>
On Wed, Jun 5, 2013 at 11:15 PM, Stack <[EMAIL PROTECTED]> wrote:

> On Thu, Jun 6, 2013 at 4:57 AM, Ted Yu <[EMAIL PROTECTED]> wrote:
>
> > bq.  I just dont find this "hbase.zookeeper.property.tickTime" anywhere
> in
> > the code base.
> >
> > Neither do I. Mind filing a JIRA to correct this in troubleshooting.xml ?
> >
>
>
> It intentionally does not exist in the hbase code base.  Read the first
> paragraph in our zookeeper chapter on how zk configs work:
> http://hbase.apache.org/book.html#zookeeper
>
>
>
> >
> > bq.  increase tickTime in zoo.cfg?
> >
> > For shared zookeeper quorum, the above should be done.
> >
> >
> What?
>
> St.Ack
>