[Linux-cluster] tmpfs on top of GFS

[Lin Shen (lshen)]

 We're trying to use it as an in-memory DB (for its speed), but need to
share the DB contents among nodes.

lin

> -----Original Message-----
> From: linux-cluster-bounces at redhat.com 
> [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Michael Will
> Sent: Thursday, January 11, 2007 3:48 PM
> To: linux clustering
> Subject: RE: [Linux-cluster] tmpfs on top of GFS
> 
> Whats the intent here? 
> 
> tmpfs is meant to be node-local temporary storage by design. 
> What are you trying to use it for?
> 
> Michael
> 
> -----Original Message-----
> From: linux-cluster-bounces at redhat.com
> [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Lin 
> Shen (lshen)
> Sent: Thursday, January 11, 2007 3:45 PM
> To: linux clustering
> Subject: RE: [Linux-cluster] tmpfs on top of GFS
> 
>  
> 
> > -----Original Message-----
> > From: linux-cluster-bounces at redhat.com 
> > [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Bryn 
> M. Reeves
> > Sent: Thursday, January 11, 2007 2:50 PM
> > To: linux clustering
> > Subject: Re: [Linux-cluster] tmpfs on top of GFS
> > 
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> > 
> > Lin Shen (lshen) wrote:
> > > If I mount a tmpfs filesystem on top of a GFS based root
> > filesystem at
> > > say /tmp, can I safely share the contents under /tmp among
> > the nodes?
> > > 
> > > lin
> > > 
> > > --
> > > Linux-cluster mailing list
> > > Linux-cluster at redhat.com
> > > https://www.redhat.com/mailman/listinfo/linux-cluster
> > 
> > Maybe I misunderstand your question, but tmpfs will not be able to 
> > share its contents between nodes the way GFS does.
> > 
> > The tmpfs filesystem uses space available in the pagecache & swap 
> > areas as a backing store instead of a dedicated block device.
> > 
> > Mounting it on top of a GFS root at /tmp is only going to 
> be visible 
> > on a single node. Each node can do that and have its own 
> tmpfs storage
> 
> > available, but this won't make the /tmp mounts shared between the 
> > cluster nodes.
> > 
> > See Documentation/filesystems/tmpfs.txt in the kernel 
> sources for more
> 
> > details.
> > 
> > Kind regards,
> > 
> > Bryn.
> > 
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> 
> I see. Can I use NFS to export tmpfs from one node to another 
> then? Or are there any other better ways to share a tmpfs 
> among the nodes.
> 
> lin 
> 
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