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From "Billy Pearson" <billy_pear...@sbcglobal.net>
Subject Re: Backup again
Date Thu, 12 Feb 2009 23:23:40 GMT

because we append edits to the edit logs by default of 300 edits per append. 
It would not be wise to copy the files with out shutting down the cluster.

multi reasons not to do this thank memcache flushes/compactions/updates all 
working on the data files and directories at the same time.

But as in all other database there if all the tables was marked as read only 
and memcache flushes was done and all compaction where done then you MIGHT 
be able to copy it. but I would not count on that to be a reliable way to do 


----- Original Message ----- 
From: "Michael Dagaev" 
Newsgroups: gmane.comp.java.hadoop.hbase.user
To: <hbase-user-7ArZoLwFLBtd/SJB6HiN2Ni2O/JbrIOy@public.gmane.org>
Sent: Thursday, February 12, 2009 11:15 AM
Subject: Re: Backup again

> Erik, thank you for the answer.
>     I am afraid my question not clear.
>     I agree that we can backup database
> just by scanning it and writing the data somewhere
> while the database is running.
>     However, if we want to backup the database
> _by copying the underlying HDFS file system_
> we have to stop the database.
> That is what I tried to say.
> M.
> On Thu, Feb 12, 2009 at 7:02 PM, Erik Holstad 
> <erikholstad-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> Hi Michael!
>> I don't think that it is true that you can only backup system that are 
>> down,
>> the backup tools that are posted in HBASE-974 can be used on system that 
>> are
>> up and running.
>> What that will do for you is to scan the tables and serialize those to 
>> disk
>> and the
>> other way around when importing.
>> Will that work for you?
>> Regards Erik
>> On Thu, Feb 12, 2009 at 2:35 AM, Michael Dagaev 
>> <michael.dagaev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>wrote:
>>> Hi, all
>>>     As I understand from the discussions on the list,
>>> we can backup the file system only if Hbase is down.
>>> If we want to run backup when Hbase is up
>>> we can work on the Hbase level, i.e. use scan,
>>> MR export/import utils, etc.  but we cannot backup
>>> on the file system level.
>>> Is it correct?
>>> Thank you for your cooperation,
>>> M.

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