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From Harsh J <ha...@cloudera.com>
Subject Re: Why hbase need to sync time between servers?
Date Thu, 08 Mar 2012 06:56:47 GMT
Moving conversation to user@hbase.apache.org, which is the right list
for HBase questions.

HBase (and many other distributed systems) rely on clocks being synced
for various operations to behave as expected. HBase does recommend
running ntpd on all nodes to keep time in proper sync. This is why it
also does a hard check of > 30s (default config, tweak-able but not
seen a really good reason yet).

See the configurations for OS that HBase demands if you deploy it, at:
http://hbase.apache.org/book.html#os

On Thu, Mar 8, 2012 at 12:20 PM, 周文辉 <cnzhwh@gmail.com> wrote:
> I installed hbase in my hadoop cluster.
> when i started hbase and i got an exception about
> ClockOutOfSyncException, somthing like this:
>
> org.apache.hadoop.hbase.ClockOutOfSyncException:
> org.apache.hadoop.hbase.ClockOutOfSyncException:
> Server slave,60020,1310983722679 has been rejected; Reported time is
> too far out of sync with
> master.  Time difference of 33514ms &gt; max allowed of 30000ms
>
> I know i need to sync the time.
>
> But does anybody know why hbase need this sync?
>
> Thanks very much!



-- 
Harsh J

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