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HBase >> mail # dev >> [DISCUSSION] Accumulo, another BigTable clone, has shown up on Apache Incubator as a proposal


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Stack 2011-09-02, 18:06
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Doug Meil 2011-09-02, 18:33
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Gary Helmling 2011-09-02, 18:40
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Todd Lipcon 2011-09-02, 19:09
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Joey Echeverria 2011-09-02, 19:30
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Ted Yu 2011-09-02, 19:37
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Joey Echeverria 2011-09-02, 19:40
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Andrew Purtell 2011-09-03, 02:06
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Gary Helmling 2011-09-02, 19:55
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Andrew Purtell 2011-09-03, 02:13
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Stack 2011-09-03, 05:17
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Bernd Fondermann 2011-09-03, 07:00
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Ryan Rawson 2011-09-03, 07:17
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Bernd Fondermann 2011-09-03, 07:55
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Ryan Rawson 2011-09-03, 09:19
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Doug Meil 2011-09-03, 13:40
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Stack 2011-09-03, 20:21
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Andrew Purtell 2011-09-04, 10:22
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Stack 2011-09-04, 22:34
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Gary Helmling 2011-09-06, 19:02
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Duane Moore 2011-09-06, 16:21
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Ted Dunning 2011-09-06, 16:31
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Stack 2011-09-06, 16:58
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Andrew Purtell 2011-09-09, 18:50
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Bradford Stephens 2011-09-09, 19:24
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Amandeep Khurana 2011-09-09, 20:28
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Andrew Purtell 2011-09-03, 10:11
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Bernd Fondermann 2011-09-02, 20:01
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Mathias Herberts 2011-09-02, 20:24
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Doug Meil 2011-09-02, 20:29
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Bernd Fondermann 2011-09-03, 06:49
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Eric Charles 2011-09-03, 19:46
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Stack 2011-09-03, 20:23
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Bill de hÓra 2011-09-03, 23:16
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Stack 2011-09-04, 02:54
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Mathias Herberts 2011-09-04, 06:43
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Ryan Rawson 2011-09-04, 06:49
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Bill 2011-09-05, 21:06
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Re: [DISCUSSION] Accumulo, another BigTable clone, has shown up on Apache Incubator as a proposal
The Accumulo implementation of the WAL is a separate set of daemons.
When you write to the WAL, you send your transactions to three of the
logging servers. When you do a recovery, I believe one of the three
servers that has the WAL for the down server copies it to HDFS and
then a MapReduce job splits the log and re-inserts the recovered data.
You should have the same survivability that you get with HDFS.

-Joey

On Mon, Sep 5, 2011 at 5:06 PM, Bill <[EMAIL PROTECTED]> wrote:
> On 04/09/11 07:43, Mathias Herberts wrote:
>>
>> On Sep 4, 2011 1:39 AM, "Bill de hÓra"<[EMAIL PROTECTED]>  wrote:
>>>
>>> On 02/09/11 19:06, Stack wrote:
>>>>
>>>> What do folks think?
>>>
>>>
>>> Not putting the log into hdfs seems like a good idea.
>>
>> I was somehow thinking the opposite as it makes irrecoverable machine
>> failures much more problematic. What makes you say it's a good idea?
>>
>
> Allows more control over the write path, specifically sequential I/O and
> crash recovery. Granted the commit needs to be replicated, but you need that
> regardless. Thinking a bit more it might not square with the regionserver
> model anyway, plus the Accumulo proposal mentions a service rather than a
> local disk. The WAL seems to be hardened up these days anyway making things
> like https://issues.apache.org/jira/browse/HBASE-4107 more of an edge case..
>
> Bill
>

--
Joseph Echeverria
Cloudera, Inc.
443.305.9434
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Doug Meil 2011-09-06, 21:51
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Bill de hÓra 2011-09-05, 20:54
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Steven Noels 2011-09-05, 08:30
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Bernd Fondermann 2011-09-05, 10:50
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Andrew Purtell 2011-09-05, 14:10
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Andrew Purtell 2011-09-05, 14:31
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Bernd Fondermann 2011-09-05, 19:32
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Andrew Purtell 2011-09-07, 01:44