Re: persistence in Hbase

You are right. The software should not get a free pass only because the hardware might lose data, though. :) From: Otis Gospodnetic To: user@hbase.apache.org; lars hofhansl Sent: Monday, January 14, 2013 7:19 PM Subject: Re: persistence in Hbase Hi, Just

Re: persistence in Hbase

This is a broad topic by itself. In short often people use battery backed cache or leave the write cache disabled for such concern. There are various factors involved when deciding if to leave caches enabled or not. Caches are often good for OLTP type application or even light OLAP workload. But fo

Re: persistence in Hbase

Hi, Just for my own edification - isn't data loss always going to be possible due to caches present in HDDs and inability(?) for force them to flush. I believe I've read even fsync lies... Thanks, Otis -- HBASE Performance Monitoring - http://sematext.com/spm/index.html On Thu, Jan 10, 2013

Re: Tune MapReduce over HBase to insert data

Hi, mohandes.zebeleh you can adjust parameter as below( Major Compaction, Minor Compaction, Split): if you do not set, it will retain default value(1). hbase.regionserver.thread.compaction.large 5 hbase.regionserver.thread.compaction.small 10 hbase.regionserver.thread.split 5 Re

Slow start of HBase operations with YCSB, possibly because of zookeeper ?

Hi hbase users, I am running HBase (on top of HDFS) in distributed mode (on 8 VMs), and things like JPS look fine on all the machines in the cluster. I am also able to run hbase shell and interact with HBase though it. But when I want to benchmark my HBase cluster with YCSB (Yahoo! Cloud System

RE: Hbase Takes Long time to Restart - Whats the correct way to

restart Hbase cluster? MIME-Version: 1.0 Content-Type: multipart/alternative; boundary=0015175cb4cee635fe04d348eb19 --0015175cb4cee635fe04d348eb19 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Is that one unassigned task even getting assigned or it errored out and won

Hbase Takes Long time to Restart - Whats the correct way to restart Hbase cluster?

I restarted Hbase master, and its taking long time (at least 30 minutes) to come back. In master-status page I am seeing over 400 regions in transition. In the hbase master log I am seeing following: DEBUG org.apache.hadoop.hbase.master.SplitLogManager: total tasks = 1 unassigned = 1 (This is

Re: best read path explanation

This in enforced in the serverside scanner framework (ScanQueryMatcher called by StoreScanner). So while expired KeyValues are only physically only removed once a compaction runs, they are logically hidden by the scanner framework. In fact the same scanner framework is used to decide whether KeyV

Re: Hbase tables disappear

What is the root directory location of hbase  Sent from Samsung Galaxy NoteIbrahim Yakti wrote:I'm using cdh4 on ec2 HBase 0.92 Sqoop 1.4.2 I'll double check versions tomorrow. when I reboot all the tables are deleted, I'll check the default location tomorrow as well. What about the weird

Re: Hbase tables disappear

I'm using cdh4 on ec2 HBase 0.92 Sqoop 1.4.2 I'll double check versions tomorrow. when I reboot all the tables are deleted, I'll check the default location tomorrow as well. What about the weird count issue? Thanks, Ibrahim Sent from another galaxy device. On Jan 14, 2013 8:22 PM, "Stack" wr

Re: Drivers for ADO.net

Hi Prabhjot, Right now, your only choices for HBase directly from a .NET client are the Thrift or REST gateways. You can find documentation about those interfaces here [0] and here [1], respectively. Best of luck, -n [0]: http://hbase.apache.org/book/thrift.html [1]: http://wiki.apache.org/hadoo

Re: best read path explanation

I have a follow up question here: A column family can be defined to have a maximum number of versions per column qualifier value. Is this enforced only by the client side code (HTable) or also by the InternalScanner implementations? On Monday, January 14, 2013, S Ahmed wrote: > Thanks Lars! > > S

Re: best read path explanation

Thanks Lars! Sort of a side question after following your proposed patch: https://issues.apache.org/jira/secure/attachment/12511771/5268-v5.txt Locally on your computer (laptop?), can those tests run in isolation or you need a fairly complicated setup to run them? (all the various hbase dependanc

Re: Hbase tables disappear

On Mon, Jan 14, 2013 at 6:12 AM, Ibrahim Yakti wrote: > Hello, > > I have a weird issue, I am using sqoop to import data from MySQL into > HBase, sqoop confirms that 2.5 million records were imported, when I do > count "table_name" in HBase shell it returns numbers like: > > 260970 row(s) in 20.4

Re: Hbase tables disappear

Hi Ibrahim, Thanks for reporting the issue you are seeing. Would you be able to provide a little more information about the version of HBase and Sqoop that you are using? Also, have you checked in HDFS to see If your data is there after reboot? -Aleks S. On Monday, January 14, 2013, Ibrahim Y

Hbase tables disappear

Hello, I have a weird issue, I am using sqoop to import data from MySQL into HBase, sqoop confirms that 2.5 million records were imported, when I do count "table_name" in HBase shell it returns numbers like: 260970 row(s) in 20.4740 seconds > (I have used sqoop to import same data from mysql to

RE: One weird problem of my MR job upon hbase table.

Hi For feedback. With a lot of profiling works, I guess I found the most promise cause of my problem. It's not because one disk is slow or something ( though I do have slow disk on different region servers, but the lagging behind pattern seems not related to the disk slowness pattern) It see