Return-Path: X-Original-To: apmail-hadoop-hdfs-user-archive@minotaur.apache.org Delivered-To: apmail-hadoop-hdfs-user-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 09DB111BE4 for ; Sat, 11 May 2013 17:23:35 +0000 (UTC) Received: (qmail 77250 invoked by uid 500); 11 May 2013 17:23:30 -0000 Delivered-To: apmail-hadoop-hdfs-user-archive@hadoop.apache.org Received: (qmail 76883 invoked by uid 500); 11 May 2013 17:23:29 -0000 Mailing-List: contact user-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@hadoop.apache.org Delivered-To: mailing list user@hadoop.apache.org Received: (qmail 76874 invoked by uid 99); 11 May 2013 17:23:29 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 11 May 2013 17:23:29 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of dontariq@gmail.com designates 209.85.212.50 as permitted sender) Received: from [209.85.212.50] (HELO mail-vb0-f50.google.com) (209.85.212.50) by apache.org (qpsmtpd/0.29) with ESMTP; Sat, 11 May 2013 17:23:25 +0000 Received: by mail-vb0-f50.google.com with SMTP id w16so4219011vbb.23 for ; Sat, 11 May 2013 10:23:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=x-received:mime-version:in-reply-to:references:from:date:message-id :subject:to:content-type; bh=ugGrr/nXfIla2cBoa+6wOqLyuM9ljH/zuXV62vqZQLs=; b=T7+jTcAHtGLIrmaOSIS6wVzn284IaM2AxVr6fd5W+fPk3pu37yT4vPinJ8wXRIW3IQ 7cKdpD8taa0Wm18g239bxSZMvGjlXjeHn/MNAhK5UjgKza0MhtQB9I3f6RIUl7u3KBht wF9Z2Q7K/etx1oWIwMM9bBGDnyW8sd7B8tdePv2AjKIRm6XytTtQO+qUL1CQevCBIIiM g0ASoE183+XbN27RJmnGOWA5GFJ8d9fy8V9vyRF295ArANBoqFUgEND6zQfZSOMM5GNZ 5brkHPTu4mTnlR+b85NotvuwR+1hZFpE1FL8gYb4sYN0hCkjFYR8k/aMTHgZV3b/9+0C mwaA== X-Received: by 10.58.234.134 with SMTP id ue6mr14459289vec.20.1368292984280; Sat, 11 May 2013 10:23:04 -0700 (PDT) MIME-Version: 1.0 Received: by 10.58.152.36 with HTTP; Sat, 11 May 2013 10:22:24 -0700 (PDT) In-Reply-To: References: From: Mohammad Tariq Date: Sat, 11 May 2013 22:52:24 +0530 Message-ID: Subject: Re: Hadoop noob question To: "user@hadoop.apache.org" Content-Type: multipart/alternative; boundary=047d7bacbcce46e2eb04dc748985 X-Virus-Checked: Checked by ClamAV on apache.org --047d7bacbcce46e2eb04dc748985 Content-Type: text/plain; charset=ISO-8859-1 You'r welcome :) Warm Regards, Tariq cloudfront.blogspot.com On Sat, May 11, 2013 at 10:46 PM, Rahul Bhattacharjee < rahul.rec.dgp@gmail.com> wrote: > Thanks Tariq! > > > On Sat, May 11, 2013 at 10:34 PM, Mohammad Tariq wrote: > >> @Rahul : Yes. distcp can do that. >> >> And, bigger the files lesser the metadata hence lesser memory consumption. >> >> Warm Regards, >> Tariq >> cloudfront.blogspot.com >> >> >> On Sat, May 11, 2013 at 9:40 PM, Rahul Bhattacharjee < >> rahul.rec.dgp@gmail.com> wrote: >> >>> IMHO,I think the statement about NN with regard to block metadata is >>> more like a general statement. Even if you put lots of small files of >>> combined size 10 TB , you need to have a capable NN. >>> >>> can disct cp be used to copy local - to - hdfs ? >>> >>> Thanks, >>> Rahul >>> >>> >>> On Sat, May 11, 2013 at 9:35 PM, Nitin Pawar wrote: >>> >>>> absolutely rite Mohammad >>>> >>>> >>>> On Sat, May 11, 2013 at 9:33 PM, Mohammad Tariq wrote: >>>> >>>>> Sorry for barging in guys. I think Nitin is talking about this : >>>>> >>>>> Every file and block in HDFS is treated as an object and for each >>>>> object around 200B of metadata get created. So the NN should be powerful >>>>> enough to handle that much metadata, since it is going to be in-memory. >>>>> Actually memory is the most important metric when it comes to NN. >>>>> >>>>> Am I correct @Nitin? >>>>> >>>>> @Thoihen : As Nitin has said, when you talk about that much data you >>>>> don't actually just do a "put". You could use something like "distcp" for >>>>> parallel copying. A better approach would be to use a data aggregation tool >>>>> like Flume or Chukwa, as Nitin has already pointed. Facebook uses their own >>>>> data aggregation tool, called Scribe for this purpose. >>>>> >>>>> Warm Regards, >>>>> Tariq >>>>> cloudfront.blogspot.com >>>>> >>>>> >>>>> On Sat, May 11, 2013 at 9:20 PM, Nitin Pawar wrote: >>>>> >>>>>> NN would still be in picture because it will be writing a lot of meta >>>>>> data for each individual file. so you will need a NN capable enough which >>>>>> can store the metadata for your entire dataset. Data will never go to NN >>>>>> but lot of metadata about data will be on NN so its always good idea to >>>>>> have a strong NN. >>>>>> >>>>>> >>>>>> On Sat, May 11, 2013 at 9:11 PM, Rahul Bhattacharjee < >>>>>> rahul.rec.dgp@gmail.com> wrote: >>>>>> >>>>>>> @Nitin , parallel dfs to write to hdfs is great , but could not >>>>>>> understand the meaning of capable NN. As I know , the NN would not be a >>>>>>> part of the actual data write pipeline , means that the data would not >>>>>>> travel through the NN , the dfs would contact the NN from time to time to >>>>>>> get locations of DN as where to store the data blocks. >>>>>>> >>>>>>> Thanks, >>>>>>> Rahul >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Sat, May 11, 2013 at 4:54 PM, Nitin Pawar < >>>>>>> nitinpawar432@gmail.com> wrote: >>>>>>> >>>>>>>> is it safe? .. there is no direct answer yes or no >>>>>>>> >>>>>>>> when you say , you have files worth 10TB files and you want to >>>>>>>> upload to HDFS, several factors come into picture >>>>>>>> >>>>>>>> 1) Is the machine in the same network as your hadoop cluster? >>>>>>>> 2) If there guarantee that network will not go down? >>>>>>>> >>>>>>>> and Most importantly I assume that you have a capable hadoop >>>>>>>> cluster. By that I mean you have a capable namenode. >>>>>>>> >>>>>>>> I would definitely not write files sequentially in HDFS. I would >>>>>>>> prefer to write files in parallel to hdfs to utilize the DFS write features >>>>>>>> to speed up the process. >>>>>>>> you can hdfs put command in parallel manner and in my experience it >>>>>>>> has not failed when we write a lot of data. >>>>>>>> >>>>>>>> >>>>>>>> On Sat, May 11, 2013 at 4:38 PM, maisnam ns wrote: >>>>>>>> >>>>>>>>> @Nitin Pawar , thanks for clearing my doubts . >>>>>>>>> >>>>>>>>> But I have one more question , say I have 10 TB data in the >>>>>>>>> pipeline . >>>>>>>>> >>>>>>>>> Is it perfectly OK to use hadopo fs put command to upload these >>>>>>>>> files of size 10 TB and is there any limit to the file size using hadoop >>>>>>>>> command line . Can hadoop put command line work with huge data. >>>>>>>>> >>>>>>>>> Thanks in advance >>>>>>>>> >>>>>>>>> >>>>>>>>> On Sat, May 11, 2013 at 4:24 PM, Nitin Pawar < >>>>>>>>> nitinpawar432@gmail.com> wrote: >>>>>>>>> >>>>>>>>>> first of all .. most of the companies do not get 100 PB of data >>>>>>>>>> in one go. Its an accumulating process and most of the companies do have a >>>>>>>>>> data pipeline in place where the data is written to hdfs on a frequency >>>>>>>>>> basis and then its retained on hdfs for some duration as per needed and >>>>>>>>>> from there its sent to archivers or deleted. >>>>>>>>>> >>>>>>>>>> For data management products, you can look at falcon which is >>>>>>>>>> open sourced by inmobi along with hortonworks. >>>>>>>>>> >>>>>>>>>> In any case, if you want to write files to hdfs there are few >>>>>>>>>> options available to you >>>>>>>>>> 1) Write your dfs client which writes to dfs >>>>>>>>>> 2) use hdfs proxy >>>>>>>>>> 3) there is webhdfs >>>>>>>>>> 4) command line hdfs >>>>>>>>>> 5) data collection tools come with support to write to hdfs like >>>>>>>>>> flume etc >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> On Sat, May 11, 2013 at 4:19 PM, Thoihen Maibam < >>>>>>>>>> thoihen123@gmail.com> wrote: >>>>>>>>>> >>>>>>>>>>> Hi All, >>>>>>>>>>> >>>>>>>>>>> Can anyone help me know how does companies like Facebook ,Yahoo >>>>>>>>>>> etc upload bulk files say to the tune of 100 petabytes to Hadoop HDFS >>>>>>>>>>> cluster for processing >>>>>>>>>>> and after processing how they download those files from HDFS to >>>>>>>>>>> local file system. >>>>>>>>>>> >>>>>>>>>>> I don't think they might be using the command line hadoop fs put >>>>>>>>>>> to upload files as it would take too long or do they divide say 10 parts >>>>>>>>>>> each 10 petabytes and compress and use the command line hadoop fs put >>>>>>>>>>> >>>>>>>>>>> Or if they use any tool to upload huge files. >>>>>>>>>>> >>>>>>>>>>> Please help me . >>>>>>>>>>> >>>>>>>>>>> Thanks >>>>>>>>>>> thoihen >>>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> -- >>>>>>>>>> Nitin Pawar >>>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> -- >>>>>>>> Nitin Pawar >>>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> Nitin Pawar >>>>>> >>>>> >>>>> >>>> >>>> >>>> -- >>>> Nitin Pawar >>>> >>> >>> >> > --047d7bacbcce46e2eb04dc748985 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
You'r welcome :)

Warm Regards,
Tariq


On Sat, May 11, 2013 at 10:46 PM, Rahul = Bhattacharjee <rahul.rec.dgp@gmail.com> wrote:
Thanks Tariq!


On S= at, May 11, 2013 at 10:34 PM, Mohammad Tariq <dontariq@gmail.com>= wrote:
@Rahul : Yes. distcp can do= that.

And, bigger the files lesser the metadata hence l= esser memory consumption.

Wa= rm Regards,
Tariq


On Sat, May 11, 2013 at 9:40 PM, Rahul B= hattacharjee <rahul.rec.dgp@gmail.com> wrote:
IMHO,I think the statement about NN with regard to block met= adata is more like a general statement. Even if you put lots of small files= of combined size 10 TB , you need to have a capable NN.

can disct cp be used to copy local - to - hdfs ?

Thanks,
=
Rahul


On Sat, May 11, 2013 at 9:35 PM, Nitin Pawar <niti= npawar432@gmail.com> wrote:
absolutely rite Mohammad=A0=


On Sat, May 11, 2013 at 9:33 PM, Mohammad Tariq <dontariq@gmail.com&g= t; wrote:
Sorry for barging in guys. = I think Nitin is talking about this :

Every file and blo= ck in HDFS is treated as an object and for each object around 200B of metad= ata get created. So the NN should be powerful enough to handle that much me= tadata, since it is going to be in-memory. Actually memory is the most impo= rtant metric when it comes to NN.=A0

Am I correct @Nitin?

@Thoihen = : As Nitin has said, when you talk about that much data you don't actua= lly just do a "put". You could use something like "distcp&qu= ot; for parallel copying. A better approach would be to use a data aggregat= ion tool like Flume or Chukwa, as Nitin has already pointed. Facebook uses = their own data aggregation tool, called Scribe for this purpose.

Wa= rm Regards,
Tariq


On Sat, May 11, 2013 at 9:20 PM, Nitin P= awar <nitinpawar432@gmail.com> wrote:
NN would still be in picture because it will be writing a = lot of meta data for each individual file. so you will need a NN capable en= ough which can store the metadata for your entire dataset. Data will never = go to NN but lot of metadata about data will be on NN so its always good id= ea to have a strong NN.


On = Sat, May 11, 2013 at 9:11 PM, Rahul Bhattacharjee <rahul.rec.dgp@gma= il.com> wrote:
@Nitin , parallel dfs to writ= e to hdfs is great , but could not understand the meaning of capable NN. As= I know , the NN would not be a part of the actual data write pipeline , me= ans that the data would not travel through the NN , the dfs would contact t= he NN from time to time to get locations of DN as where to store the data b= locks.

Thanks,
Rahul



On Sat, May 1= 1, 2013 at 4:54 PM, Nitin Pawar <nitinpawar432@gmail.com> wrote:
is it safe? .. there is no = direct answer yes or no=A0

when you say , you have files= worth 10TB files and you want to upload =A0to HDFS, several factors come i= nto picture=A0

1) Is the machine in the same network as your hadoop cluster= ?
2) If there guarantee that network will not go down?
=
and Most importantly I assume that you have a capable hadoop= cluster. By that I mean you have a capable namenode.=A0

I would definitely not write files=A0sequentially=A0in = HDFS. I would prefer to write files in parallel=A0to hdfs to utilize the DF= S write features to speed up the process.=A0
you can hdfs put com= mand in parallel manner and in my experience it has not failed when we writ= e a lot of data.=A0


On Sat, May 11, 2013 at 4:38 PM, maisnam ns <maisnam.ns@gmail.com> wrote:
@Nitin Pawar= , thanks for clearing my doubts .

But I have one more questio= n , say I have 10 TB data in the pipeline .

Is it perfectly OK to use hadopo fs put command to upload these f= iles of size 10 TB and is there any limit to the file size=A0 using hadoop = command line . Can hadoop put command line work with huge data.

Thanks in advance
<= br>
On Sat, May 11, 2013 at 4:24 PM, Nitin Pa= war <nitinpawar432@gmail.com> wrote:
first of all .. most of the= companies do not get 100 PB of data in one go. Its an accumulating process= and most of the companies do have a data pipeline in place where the data = is written to hdfs on a frequency basis and =A0then its retained on hdfs fo= r some duration as per needed and from there its sent to archivers or delet= ed.=A0

For data management products, you can look at falcon which i= s open sourced by inmobi along with hortonworks.=A0

In any case, if you want to write files to hdfs there are few options ava= ilable to you
1) Write your dfs client which writes to dfs
2) use hdfs pro= xy
3) there is webhdfs
4) command line hdfs
5= ) data collection tools come with support to write to hdfs like flume etc


On Sat, May 11, 2013 at 4:19 PM, Thoihen Maibam <thoihen123@gmail.co= m> wrote:
Hi All,

Can anyone help me know how does companies like Fac= ebook ,Yahoo etc upload bulk files say to the tune of 100 petabytes to Hado= op HDFS cluster for processing
and after processing how they download those files from HDFS to = local file system.

I don't think they might be = using the command line hadoop fs put to upload files as it would take too l= ong or do they divide say 10 parts each 10 petabytes and=A0 compress and us= e the command line hadoop fs put

Or if they use any tool to upload huge files.

Please= help me .

Thanks
thoihen



<= font color=3D"#888888">--
Nitin Pawar




<= /div>--
Nitin Pawar




<= /div>--
Nitin Pawar




<= font color=3D"#888888">--
Nitin Pawar




--047d7bacbcce46e2eb04dc748985--