RES: [Linux-cluster] GFS Performance advise

Lon Hohberger lhh at
Thu Jul 27 17:06:50 UTC 2006

On Thu, 2006-07-27 at 13:03 -0400, Lon Hohberger wrote:
> On Wed, 2006-07-26 at 09:36 -0300, Leonardo Rodrigues de Mello wrote:
> > Gfs is only necessary if you have two or more machines that access (READ+WRITE) the filesystem at the same time. GFS will create and manage a global lock of the filesystem, and other things to make shure the filesystem can be shared among the cluster nodes without filesystem corruption.

> > beside that fact, if you have active/passive you can use ext3 without any problem. you can use gfs no_lock too. if you are having problems with gfs no_lock maybe because something is misconfigured in your setup. You CANT use gfs no_lock the same way you use gfs with dlm or gulm because if you do that you can get a filesystem corruption... i dont know if gfs permit one configuration like that. 

You're absolutely right.

> Note that both read caching (in all cases) and write caching (in the
> case of the single read/write node) while using ext3 will cause observed
> inconsistencies in the file system (and files), even though file system
> corruption may not be the end result.

I'm sorry, I read that as "multiple readers / one writer" (e.g. several
machines mounting the same ext3 fs at the same time [bad idea]), even
though you said "active / passive"; e.g. "one mounter at a time".

-- Lon

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