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

Simon Thompson S.J.Thompson at bham.ac.uk
Thu Nov 19 19:37:52 GMT 2020


My understanding was that this was perfectly acceptable in a GPFS system. i.e. mounting parts of file-systems in others. It has been suggested to us as a way of using different vendor GPFS systems (e.g. an ESS with someone elses) as a way of working round the licensing rules about ESS and anything else, but still giving a single user “name space”. We didn’t go that route, and of course I might have misunderstood what was being suggested.

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 18:13
To: "gpfsug-discuss at spectrumscale.org" <gpfsug-discuss at spectrumscale.org>
Subject: Re: [gpfsug-discuss] Mounting filesystem on top of an existing filesystem




Hi all,



thanks a lot for your comments. Agreed, I better avoid it for now. I was concerned about how GPFS would behave in such case. For production I will take the safe route, but, just out of curiosity, I'll give it a try on a couple of test filesystems.



Thanks a lot for your help, it was very helpful,

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 Skylar Thompson <skylar2 at uw.edu>
Sent: Thursday, November 19, 2020 6:38:07 PM
To: gpfsug-discuss at spectrumscale.org
Subject: Re: [gpfsug-discuss] Mounting filesystem on top of an existing filesystem

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
> >

> _______________________________________________
> gpfsug-discuss mailing list
> gpfsug-discuss at spectrumscale.org
> http://gpfsug.org/mailman/listinfo/gpfsug-discuss


--
-- Skylar Thompson (skylar2 at u.washington.edu)
-- Genome Sciences Department (UW Medicine), System Administrator
-- Foege Building S046, (206)-685-7354
-- Pronouns: He/Him/His
_______________________________________________
gpfsug-discuss mailing list
gpfsug-discuss at spectrumscale.org
http://gpfsug.org/mailman/listinfo/gpfsug-discuss
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://gpfsug.org/pipermail/gpfsug-discuss_gpfsug.org/attachments/20201119/b648e4d1/attachment-0002.htm>


More information about the gpfsug-discuss mailing list