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From Hayati Gonultas <hayati.gonul...@gmail.com>
Subject Re: HDFS2 vs MaprFS
Date Sun, 05 Jun 2016 14:29:47 GMT
No it is Not true. it totally depends of server's Ram.

Assume that each file holds 1k on Ram and your server has 128gb of ram. So
you will have 128 000 000 million file. But 1k is just approximation.
Raughtly 1gb holds 1million blocks. So if your server has 512gb of ram then
you can approximately hold 512million blocks.
5 Haz 2016 16:58 tarihinde "Ascot Moss" <ascot.moss@gmail.com> yazd─▒:

> HDFS2 "Limit to 50-200 million files", is it really true like what MapR
> says?
> On Sun, Jun 5, 2016 at 7:55 PM, Hayati Gonultas <hayati.gonultas@gmail.com
> > wrote:
>> I forgot to mention about file system limit.
>> Yes HDFS has limit, because for the performance considirations HDFS
>> filesystem is read from disk to RAM and rest of the work is done with RAM.
>> So RAM should be big enough to fit the filesystem image. But HDFS has
>> configuration options like har files (Hadoop Archive) to defeat these
>> limitations.
>> On Sun, Jun 5, 2016 at 11:14 AM, Ascot Moss <ascot.moss@gmail.com> wrote:
>>> Will the the common pool of datanodes and namenode federation be a more
>>> effective alternative in HDFS2  than multiple clusters?
>>> On Sun, Jun 5, 2016 at 12:19 PM, daemeon reiydelle <daemeonr@gmail.com>
>>> wrote:
>>>> There are indeed many tuning points here. If the name nodes and journal
>>>> nodes can be larger, perhaps even bonding multiple 10gbyte nics, one can
>>>> easily scale. I did have one client where the file counts forced multiple
>>>> clusters. But we were able to differentiate by airframe types ... eg fixed
>>>> wing in one, rotary subsonic in another, etc.
>>>> sent from my mobile
>>>> Daemeon C.M. Reiydelle
>>>> USA 415.501.0198
>>>> London +
>>>> On Jun 4, 2016 2:23 PM, "Gavin Yue" <yue.yuanyuan@gmail.com> wrote:
>>>>> Here is what I found on Horton website.
>>>>> *Namespace scalability*
>>>>> While HDFS cluster storage scales horizontally with the addition of
>>>>> datanodes, the namespace does not. Currently the namespace can only be
>>>>> vertically scaled on a single namenode.  The namenode stores the entire
>>>>> file system metadata in memory. This limits the number of blocks, files,
>>>>> and directories supported on the file system to what can be accommodated
>>>>> the memory of a single namenode. A typical large deployment at Yahoo!
>>>>> includes an HDFS cluster with 2700-4200 datanodes with 180 million
>>>>> files and blocks, and address ~25 PB of storage.  At Facebook, HDFS has
>>>>> around 2600 nodes, 300 million files and blocks, addressing up to 60PB
>>>>> storage. While these are very large systems and good enough for majority
>>>>> Hadoop users, a few deployments that might want to grow even larger could
>>>>> find the namespace scalability limiting.
>>>>> On Jun 4, 2016, at 04:43, Ascot Moss <ascot.moss@gmail.com> wrote:
>>>>> Hi,
>>>>> I read some (old?) articles from Internet about Mapr-FS vs HDFS.
>>>>> https://www.mapr.com/products/m5-features/no-namenode-architecture
>>>>> It states that HDFS Federation has
>>>>> a) "Multiple Single Points of Failure", is it really true?
>>>>> Why MapR uses HDFS but not HDFS2 in its comparison as this would lead
>>>>> to an unfair comparison (or even misleading comparison)?  (HDFS was from
>>>>> Hadoop 1.x, the old generation) HDFS2 is available since 2013-10-15,
>>>>> is no any Single Points of  Failure in HDFS2.
>>>>> b) "Limit to 50-200 million files", is it really true?
>>>>> I have seen so many real world Hadoop Clusters with over 10PB data,
>>>>> some even with 150PB data.  If "Limit to 50 -200 millions files" were
>>>>> in HDFS2, why are there so many production Hadoop clusters in real world?
>>>>> how can they mange well the issue of  "Limit to 50-200 million files"?
>>>>> instances,  the Facebook's "Like" implementation runs on HBase at Web
>>>>> Scale, I can image HBase generates huge number of files in Facbook's
>>>>> cluster, the number of files in Facebook's Hadoop cluster should be much
>>>>> much bigger than 50-200 million.
>>>>> From my point of view, in contrast, MaprFS should have true limitation
>>>>> up to 1T files while HDFS2 can handle true unlimited files, please do
>>>>> correct me if I am wrong.
>>>>> c) "Performance Bottleneck", again, is it really true?
>>>>> MaprFS does not have namenode in order to gain file system
>>>>> performance. If without Namenode, MaprFS would lose Data Locality which
>>>>> one of the beauties of Hadoop  If Data Locality is no longer available,
>>>>> big data application running on MaprFS might gain some file system
>>>>> performance but it would totally lose the true gain of performance from
>>>>> Data Locality provided by Hadoop's namenode (gain small lose big)
>>>>> d) "Commercial NAS required"
>>>>> Is there any wiki/blog/discussion about Commercial NAS on Hadoop
>>>>> Federation?
>>>>> regards
>> --
>> Hayati Gonultas

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