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HBase >> mail # user >> HBase Fault tolerance


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Re: HBase Fault tolerance
> My question is how is this HLog file different from a StoreFile? Why is it
> faster to write to an HLog file and not write directly to a StoreFile?

Read this: http://www.larsgeorge.com/2010/01/hbase-architecture-101-write-ahead-log.html
and http://www.larsgeorge.com/2009/10/hbase-architecture-101-storage.html

--Suraj
On Fri, Jul 13, 2012 at 3:42 AM, Sever Fundatureanu
<[EMAIL PROTECTED]> wrote:
> Hello,
>
> I would like to understand more in-depth how fault tolerance is handled in
> HBase:
>
> 1. So for each put operation an RS first writes to an HLog file and then to
> the Memstore. If the RS crashes the HLog file is replayed by other servers,
> correct?
> My question is how is this HLog file different from a StoreFile? Why is it
> faster to write to an HLog file and not write directly to a StoreFile?
>
> 2. How is fault tolerance handled for an RS with a coprocessor loaded? Will
> other servers load that coprocessor if the original RS crashes? If yes,
> will the HLog be replayed with the coprocessor already loaded?
>
> Thanks in advance for the responses.
> --
> Sever Fundatureanu
>
> Vrije Universiteit Amsterdam
> E-mail: [EMAIL PROTECTED]