Gluster users - Apr 2012 - Setting up a 2 sites replication with access to files from both sites

Hello, 

This is my first post to the list. 

I have 2 distant sites
linked through a 10MBits MPLS. 

To improve user experience, we would
like to setup a replicated glusterfs on the 2 sites, such that a user on
site A would access the files from site A replicated server, and a user
on site B would access the files from site B replicated server. 

So I
was thinking of a dual server setup, each being client and server for
its site, so that read access to files would be fast, and write access
would be as fast as MPLS allows it to be. 

The files would then be
shared using samba to the users. 

In this situation, I don't know if I
should prefer client side AFR or server side AFR (I guess server side
AFR would make the files on both sites unavailable if MPLS fails).


Anyway, I gave a test drive on this, and seem to be having locking
issues (users on both side can modify the same file without anything
preventing this). 

Can anybody comment on this. 

Thanks in advance.


Fran?ois 
 
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On Fri, Apr 06, 2012 at 04:24:54PM +0200, Fran?ois Legal
wrote:
>    Anyway, I gave a test drive on this, and seem to be having locking
>    issues (users on both side can modify the same file without anything
>    preventing this).
> 
>    Can anybody comment on this.
That's just POSIX semantics. You could even have two users on the same
machine accessing the same file and modifying it concurrently. If you want
locks then (a) your application has to ask for them, and (b) other
applications must also respect them [unless you're talking about mandatory
locks, which are an unusual feature]

I am not aware of a mechanism where you can force a read from only one brick,
but write to both, short of having reads done out of a totally separate
directory structure.

Someone can correct me if this is wrong, but that is how my replica
configuration behaves w/ 3.2.5.

David



On Apr 6, 2012, at 10:24 AM, Fran?ois Legal wrote:
> Hello,
> 
>  
> This is my first post to the list.
> 
>  
> I have 2 distant sites linked through a 10MBits MPLS.
> 
> To improve user experience, we would like to setup a replicated glusterfs
on the 2 sites, such that a user on site A would access the files from site A
replicated server, and a user on site B would access the files from site B
replicated server.
> 
> So I was thinking of a dual server setup, each being client and server for
its site, so that read access to files would be fast, and write access would be
as fast as MPLS allows it to be.
> 
> The files would then be shared using samba to the users.
> 
>  
> In this situation, I don't know if I should prefer client side AFR or
server side AFR (I guess server side AFR would make the files on both sites
unavailable if MPLS fails).
> 
>  
> Anyway, I gave a test drive on this, and seem to be having locking issues
(users on both side can modify the same file without anything preventing this).
> 
>  
> Can anybody comment on this.
> 
>  
> Thanks in advance.
> 
>  
> Fran?ois
> 
>  
> _______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
> http://gluster.org/cgi-bin/mailman/listinfo/gluster-users
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