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From Doug Meil <doug.m...@explorysmedical.com>
Subject Re: A requirement to change time of the Hbase cluster.
Date Wed, 26 Oct 2011 13:22:20 GMT
Hi there-

As a reminder about running without an NTP server, the config section of
the book strongly cautions against this:

http://hbase.apache.org/book.html#ntp





On 10/25/11 10:36 PM, "Gaojinchao" <gaojinchao@huawei.com> wrote:

>Thanks for your reply.
>Our application scenario, The equipment and network is not our, Operators
>may do some of the equipment and network adjustment.
>In this case, These are some of the uncertainties.
>So we hope to add a choice about metadata is not time-dependent. Just
>like use data can use a number as a timestamp .
>If we can do this, the effect for time will be smaller. We don't use the
>ntp server, the cluster also can work normal ?
>Can I open a file? I will try to make a patch and share my mind.
>
>-----邮件原件-----
>发件人: Michel Segel [mailto:michael_segel@hotmail.com]
>发送时间: 2011年10月26日 3:55
>收件人: user@hbase.apache.org
>抄送: user@hbase.apache.org
>主题: Re: A requirement to change time of the Hbase cluster.
>
>Maybe I'm missing something...
>
>The purpose of using an ntp server is that your machines all have the
>same time. Also you would sync your ntp server clock to one of the global
>ntp servers so that you have an accurate clock for your network...
>
>You shouldn't have to restart your cluster unless your clocks are all way
>off...
>
>Sent from a remote device. Please excuse any typos...
>
>Mike Segel
>
>On Oct 25, 2011, at 5:14 AM, Gaojinchao <gaojinchao@huawei.com> wrote:
>
>> Perhaps we should. add a choice of supporting incremental meta-data.
>>All the timestamp is incremental, These data do not rely on the system
>>time.
>> 
>> -----邮件原件-----
>> 发件人: Gaojinchao [mailto:gaojinchao@huawei.com]
>> 发送时间: 2011年10月25日 12:33
>> 收件人: user@hbase.apache.org
>> 主题: A requirement to change time of the Hbase cluster.
>> 
>> Hi all,
>> We have a requirement to change time of the Hbase cluster.
>> The scene is the cluster changes the ntp server(my customer may do
>>this),
>> We are ready to do this:
>> 1. stop the cluster
>> 2. change the ntp server
>> 3. start the cluster.
>> But the cluster may move to one ntp server which system is slower.
>> we find the meta data can't update becuase newly added record is
>>covered by old record and the cluster don't run normal.
>> I have a way to deal with this situation. before we update the meta
>>data ,we can get it firstly and then compare the timestamp with the
>>system time.
>> if system time is lower than timestamp, updating metadata can use as
>>timestamp +1.

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