[gpfsug-discuss] Mounting filesystem on top of an existing filesystem

[Skylar Thompson]

Agreed, not sure how the GPFS tools would react. An alternative to symlinks
would be bind mounts, if for some reason a tool doesn't behave properly
with a symlink in the path.

On Thu, Nov 19, 2020 at 06:34:05PM +0100, Jan-Frode Myklebust wrote:
> I would not mount a GPFS filesystem within a GPFS filesystem. Technically
> it should work, but I???d expect it to cause surprises if ever the lower
> filesystem experienced problems. Alone, a filesystem might recover
> automatically by remounting. But if there???s another filesystem mounted
> within, I expect it will be a problem..
> 
> Much better to use symlinks.
> 
> 
> 
>   -jf
> 
> tor. 19. nov. 2020 kl. 18:01 skrev Caubet Serrabou Marc (PSI) <
> marc.caubet at psi.ch>:
> 
> > Hi Simon,
> >
> >
> > that's a very good point, thanks a lot :) I have it remotely mounted on a
> > client cluster, so I will consider priorities when mounting the filesystems
> > with remote cluster mount. That's very useful.
> >
> > Also, as far as I saw, same approach can be also applied to local mounts
> > (via mmchfs) during daemon startup with the same option --mount-priority.
> >
> >
> > Thanks a lot for the hints, these are very useful. I'll test that.
> >
> >
> > Cheers,
> >
> > Marc
> > _________________________________________________________
> > Paul Scherrer Institut
> > High Performance Computing & Emerging Technologies
> > Marc Caubet Serrabou
> > Building/Room: OHSA/014
> > Forschungsstrasse, 111
> > 5232 Villigen PSI
> > Switzerland
> >
> > Telephone: +41 56 310 46 67
> > E-Mail: marc.caubet at psi.ch
> > ------------------------------
> > *From:* gpfsug-discuss-bounces at spectrumscale.org <
> > gpfsug-discuss-bounces at spectrumscale.org> on behalf of Simon Thompson <
> > S.J.Thompson at bham.ac.uk>
> > *Sent:* Thursday, November 19, 2020 5:42:07 PM
> > *To:* gpfsug main discussion list
> > *Subject:* Re: [gpfsug-discuss] Mounting filesystem on top of an existing
> > filesystem
> >
> >
> > If it is a remote cluster mount from your clients (hopefully!), you might
> > want to look at priority to order mounting of the file-systems. I don???t
> > know what would happen if the overmounted file-system went away, you would
> > likely want to test.
> >
> >
> >
> > Simon
> >
> >
> >
> > *From: *<gpfsug-discuss-bounces at spectrumscale.org> on behalf of "
> > marc.caubet at psi.ch" <marc.caubet at psi.ch>
> > *Reply to: *"gpfsug-discuss at spectrumscale.org" <
> > gpfsug-discuss at spectrumscale.org>
> > *Date: *Thursday, 19 November 2020 at 15:39
> > *To: *"gpfsug-discuss at spectrumscale.org" <gpfsug-discuss at spectrumscale.org
> > >
> > *Subject: *[gpfsug-discuss] Mounting filesystem on top of an existing
> > filesystem
> >
> >
> >
> > Hi,
> >
> >
> >
> > I have a filesystem holding many projects (i.e., mounted under /projects),
> > each project is managed with filesets.
> >
> > I have a new big project which should be placed on a separate filesystem
> > (blocksize, replication policy, etc. will be different, and subprojects of
> > it will be managed with filesets). Ideally, this filesystem should be
> > mounted in /projects/newproject.
> >
> >
> >
> > Technically, mounting a filesystem on top of an existing filesystem should
> > be possible, but, is this discouraged for any reason? How GPFS would behave
> > with that and is there a technical reason for avoiding this setup?
> >
> > Another alternative would be independent mount point + symlink, but I
> > really would prefer to avoid symlinks.
> >
> >
> >
> > Thanks a lot,
> >
> > Marc
> >
> > _________________________________________________________
> > Paul Scherrer Institut
> > High Performance Computing & Emerging Technologies
> > Marc Caubet Serrabou
> > Building/Room: OHSA/014
> >
> > Forschungsstrasse, 111
> >
> > 5232 Villigen PSI
> > Switzerland
> >
> > Telephone: +41 56 310 46 67
> > E-Mail: marc.caubet at psi.ch
> > _______________________________________________
> > gpfsug-discuss mailing list
> > gpfsug-discuss at spectrumscale.org
> > http://gpfsug.org/mailman/listinfo/gpfsug-discuss
> >

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-- 
-- Skylar Thompson (skylar2 at u.washington.edu)
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