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From Amr Awadallah <...@cloudera.com>
Subject Re: input/output error while setting up superblock
Date Fri, 22 May 2009 21:43:24 GMT

You should take a look at GlusterFS, it should be a good fit for this
kind of workload:

http://www.gluster.org/

-- amr

Aaron Kimball wrote:
> More specifically:
>
> HDFS does not support operations such as opening a file for write/append
> after it has already been closed, or seeking to a new location in a writer.
> You can only write files linearly; all other operations will return a "not
> supported" error.
>
> You'll also find that random-access read performance, while implemented, is
> not particularly high-throughput. For serving Xen images even in read-only
> mode, you'll likely have much better luck with a different FS.
>
> - Aaron
>
>
> 2009/5/22 Taeho Kang <tkang1@gmail.com>
>
>   
>> I don't think HDFS is a good place to store your Xen image file as it will
>> likely be updated/appended frequently in small blocks. With the way HDFS is
>> designed for, you can't quite use it like a regular filesystem (e.g. ones
>> that support frequent small block appends/updates in files). My suggestion
>> is to use another filesystem like NAS or SAN.
>>
>> /Taeho
>>
>> 2009/5/22 신승엽 <mikasa83@naver.com>
>>
>>     
>>> Hi, I have a problem to use hdfs.
>>>
>>> I mounted hdfs using fuse-dfs.
>>>
>>> I created a dummy file for 'Xen' in hdfs and then formated the dummy file
>>> using 'mke2fs'.
>>>
>>> But the operation was faced error. The error message is as follows.
>>>
>>> [root@localhost hdfs]# mke2fs -j -F ./file_dumy
>>> mke2fs 1.40.2 (12-Jul-2007)
>>> ./file_dumy: Input/output error while setting up superblock
>>> Also, I copyed an image file of xen to hdfs. But Xen couldn't the image
>>> files in hdfs.
>>>
>>> root@localhost hdfs]# fdisk -l fedora6_demo.img
>>> last_lba(): I don't know how to handle files with mode 81a4
>>> You must set cylinders.
>>> You can do this from the extra functions menu.
>>>
>>> Disk fedora6_demo.img: 0 MB, 0 bytes
>>> 255 heads, 63 sectors/track, 0 cylinders
>>> Units = cylinders of 16065 * 512 = 8225280 bytes
>>>
>>>           Device Boot      Start         End      Blocks   Id  System
>>> fedora6_demo.img1   *           1         156     1253038+  83  Linux
>>>
>>> Could you answer me anything about this problem.
>>>
>>> Thank you.
>>>
>>>       
>
>   

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