[Gluster-users] read consistency amongst bricks / sync writes

[Whit Blauvelt]

On Tue, Apr 19, 2011 at 05:33:58PM +0200, Vincent Thomasset wrote:

> This is a newbie question as i am relatively new to glusterfs but
> nonetheless... :)
> 
> I believe the file propagation is asynchronous between the bricks and was
> wondering whether a subsequent write to a file and read of that same file could
> possibly happen on different bricks, so that the following scenario
> would happen:
> 
> - write on brick a
> - read on brick b (file not found)

I'm new too, but we've been discussing this recently here. My understanding
is that files are written synchronously as long as you address your gluster
file system through a client (either gluster or nfs), and not directly
through through the local mount as an ext3/ext4 system. 

The exception would be when one of the systems is inaccessible. In that case
it will take "healing" later - that is, running through the file system with
"find" or the like through a gluster client - to bring the system that was
unavailable up to date.

Hopefully if I don't quite have this right, the more knowledgeable will step
in. 

Whit