[Linux-cluster] Re: Synchronized filesystem

[Jan-Frode Myklebust]

On 2005-12-29, Jean-Eric <jec at rptec.ch> wrote:
>
> Yes, I want local caching but also transparent writes. If I'm in the UK 
> I want to write FileServerInTheUk (ans that goes auto to 
> FileServerInTheUS which holds the storage) and if I'm in the US, I want 

I think what you want is something like IBM's GPFS, which is similar to GFS, 
but also support replication over 2 sets of storage nodes. ie. you define 
US_storage_nodes and UK_storage_nodes, and tell gpfs to keep 2 copies of 
every block in 2 different replication sets.

If you read and write in US, everything will happen locally and writes will be
replicated to UK in the background. 

But, if you lose the link between the sites, only one of the sites will be able 
to continue operating (by having a majority of the quorum nodes). Also I think
the 2 MBit link would probably not be sufficient if you need to do a re-replication
of the full file system..


  -jf