[ale] XFS multi-mount

[Dow Hurst]

Greg is on the right path here.  A cluster file system Raided would be 
the best bet.  Your close, just look into CXFS if you want SGI's cluster 
file system.  Lot's of options there and I bet they use it on the Altix 
so it is ported onto Linux.  I don't know it myself so you'll have to go 
look.  It would be cool if you don't even have to do anything other than 
just add CXFS to your machines.  It may work with XFS filesystems by 
default.
dow


Greg Freemyer wrote:

>Attriel,
>
>I assume you know that what you are doing is simply not supported by
>most filesystems, right?
>
>The "correct" thing to do would be to try a cluster filesystem. 
>
>For what you describe, I think GFS from Redhat or OCFS from Oracle
>would be the best GPL choices.  Both are designed  to have multiple
>nodes accessing a common shared storage array.
>
>Unfortunately neither of these is likely to be as fast as XFS.  
>
>I would check out OCFS first.  It has some short-comings (no locking,
>no acls, etc.),  but I don't think you need those features.
>
>If you need XFS, you could also try mounting with the sync flag.  That
>tells xfs to keep the servers write buffer flushed to disk at all
>times.  Unfortunately, the sync flag really slows down XFS's
>performance.
>
>That would fix your write caching issues.
>
>As Dow said, it is your read cache that is likely the real difficulty.
> Maybe you could post on the XFS list and someone could tell you of
>way to invalidate all the read cache pages, thus forcing a physical
>read.  If that could be done every 30 seconds or so, it might work for
>you.
>
>Greg
>  
>