Gluster users - May 2011 - What will happen if one file size exceeds the available node's harddrive capacity?

Hi, all
    I have a question about the capacity problem in GlusterFS cluster system.
    Supposedly, we have a cluster configuration like this:
    
    Type: Distributed-Replicate
    Number of Bricks: 2 x 1 = 2
    Brick1: 192.168.1.150:/home/export
    Brick2: 192.168.1.151:/home/export

    If there are only 15 Giga bytes available in these two servers, and I need
to copy a file of 20GB to the the mounted directory. Obviously the space is not
enough.
    Then I add two bricks of 15GB to the cluster. The structure became to:
    
    Type: Distributed-Replicate
    Number of Bricks: 2 x 2 = 4
    Bricks:
    Brick1: 192.168.1.152:/home/export/dfsStore
    Brick2: 192.168.1.153:/home/export/dfsStore
    Brick3: 192.168.1.150:/home/export/dfsStore
    Brick4: 192.168.1.151:/home/export/dfsStore
  
    Now I will copy the file again to the mounted directory. In client, it shows
it has more than 20GB space available. But what will happen when I copy the huge
file to it since every single brick doesn't have enough space to hold it.
    
    Thanks a lot.

Yueyu Lin <yueyu.lin at me.com> ?????(?) ? ????? ?????? Tue, 03 May 2011  
12:48:41 +0400:
>    Now I will copy the file again to the mounted directory. In client,  
> it shows it has more than 20GB space available. But what will happen  
> when I copy the huge file to it since every single brick doesn't have  
> enough space to hold it.
Haven't tried it, but most probably, it won't work. Distribute algorithm
distributes files between bricks, but it has nothing to do with the file  
data itself. So, if the file won't fit on any brick completely, it won't
fit at all.

I just made the experiment. The answer is no. Distributed-Replicate mode
won't split images for application. Application has to split the huge file
manually.
On May 3, 2011, at 4:48 PM, Yueyu Lin wrote:
> Hi, all
>    I have a question about the capacity problem in GlusterFS cluster
system.
>    Supposedly, we have a cluster configuration like this:
> 
>    Type: Distributed-Replicate
>    Number of Bricks: 2 x 1 = 2
>    Brick1: 192.168.1.150:/home/export
>    Brick2: 192.168.1.151:/home/export
> 
>    If there are only 15 Giga bytes available in these two servers, and I
need to copy a file of 20GB to the the mounted directory. Obviously the space is
not enough.
>    Then I add two bricks of 15GB to the cluster. The structure became to:
> 
>    Type: Distributed-Replicate
>    Number of Bricks: 2 x 2 = 4
>    Bricks:
>    Brick1: 192.168.1.152:/home/export/dfsStore
>    Brick2: 192.168.1.153:/home/export/dfsStore
>    Brick3: 192.168.1.150:/home/export/dfsStore
>    Brick4: 192.168.1.151:/home/export/dfsStore
> 
>    Now I will copy the file again to the mounted directory. In client, it
shows it has more than 20GB space available. But what will happen when I copy
the huge file to it since every single brick doesn't have enough space to
hold it.
> 
>    Thanks a lot. 
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