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<p class="MsoNormal"><span style="mso-fareast-language:EN-US">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.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US">Simon<o:p></o:p></span></p>
<p class="MsoNormal"><span style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black"><gpfsug-discuss-bounces@spectrumscale.org> on behalf of "marc.caubet@psi.ch" <marc.caubet@psi.ch><br>
<b>Reply to: </b>"gpfsug-discuss@spectrumscale.org" <gpfsug-discuss@spectrumscale.org><br>
<b>Date: </b>Thursday, 19 November 2020 at 18:13<br>
<b>To: </b>"gpfsug-discuss@spectrumscale.org" <gpfsug-discuss@spectrumscale.org><br>
<b>Subject: </b>Re: [gpfsug-discuss] Mounting filesystem on top of an existing filesystem<o:p></o:p></span></p>
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<p><span style="font-size:12.0pt;color:black">Hi all,<o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
<p><span style="font-size:12.0pt;color:black">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.<o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
<p><span style="font-size:12.0pt;color:black">Thanks a lot for your help, it was very helpful,<o:p></o:p></span></p>
<p><span style="font-size:12.0pt;color:black">Marc <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">_________________________________________________________<br>
Paul Scherrer Institut <br>
High Performance Computing & Emerging Technologies<br>
Marc Caubet Serrabou<br>
Building/Room: OHSA/014<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">Forschungsstrasse, 111<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma",sans-serif;color:black">5232 Villigen PSI<br>
Switzerland<br>
<br>
Telephone: +41 56 310 46 67<br>
E-Mail: marc.caubet@psi.ch<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="color:black">From:</span></b><span style="color:black"> gpfsug-discuss-bounces@spectrumscale.org <gpfsug-discuss-bounces@spectrumscale.org> on behalf of Skylar Thompson <skylar2@uw.edu><br>
<b>Sent:</b> Thursday, November 19, 2020 6:38:07 PM<br>
<b>To:</b> gpfsug-discuss@spectrumscale.org<br>
<b>Subject:</b> Re: [gpfsug-discuss] Mounting filesystem on top of an existing filesystem</span><span style="font-size:12.0pt;color:black">
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;color:black">Agreed, not sure how the GPFS tools would react. An alternative to symlinks<br>
would be bind mounts, if for some reason a tool doesn't behave properly<br>
with a symlink in the path.<br>
<br>
On Thu, Nov 19, 2020 at 06:34:05PM +0100, Jan-Frode Myklebust wrote:<br>
> I would not mount a GPFS filesystem within a GPFS filesystem. Technically<br>
> it should work, but I???d expect it to cause surprises if ever the lower<br>
> filesystem experienced problems. Alone, a filesystem might recover<br>
> automatically by remounting. But if there???s another filesystem mounted<br>
> within, I expect it will be a problem..<br>
> <br>
> Much better to use symlinks.<br>
> <br>
> <br>
> <br>
> -jf<br>
> <br>
> tor. 19. nov. 2020 kl. 18:01 skrev Caubet Serrabou Marc (PSI) <<br>
> marc.caubet@psi.ch>:<br>
> <br>
> > Hi Simon,<br>
> ><br>
> ><br>
> > that's a very good point, thanks a lot :) I have it remotely mounted on a<br>
> > client cluster, so I will consider priorities when mounting the filesystems<br>
> > with remote cluster mount. That's very useful.<br>
> ><br>
> > Also, as far as I saw, same approach can be also applied to local mounts<br>
> > (via mmchfs) during daemon startup with the same option --mount-priority.<br>
> ><br>
> ><br>
> > Thanks a lot for the hints, these are very useful. I'll test that.<br>
> ><br>
> ><br>
> > Cheers,<br>
> ><br>
> > Marc<br>
> > _________________________________________________________<br>
> > Paul Scherrer Institut<br>
> > High Performance Computing & Emerging Technologies<br>
> > Marc Caubet Serrabou<br>
> > Building/Room: OHSA/014<br>
> > Forschungsstrasse, 111<br>
> > 5232 Villigen PSI<br>
> > Switzerland<br>
> ><br>
> > Telephone: +41 56 310 46 67<br>
> > E-Mail: marc.caubet@psi.ch<br>
> > ------------------------------<br>
> > *From:* gpfsug-discuss-bounces@spectrumscale.org <<br>
> > gpfsug-discuss-bounces@spectrumscale.org> on behalf of Simon Thompson <<br>
> > S.J.Thompson@bham.ac.uk><br>
> > *Sent:* Thursday, November 19, 2020 5:42:07 PM<br>
> > *To:* gpfsug main discussion list<br>
> > *Subject:* Re: [gpfsug-discuss] Mounting filesystem on top of an existing<br>
> > filesystem<br>
> ><br>
> ><br>
> > If it is a remote cluster mount from your clients (hopefully!), you might<br>
> > want to look at priority to order mounting of the file-systems. I don???t<br>
> > know what would happen if the overmounted file-system went away, you would<br>
> > likely want to test.<br>
> ><br>
> ><br>
> ><br>
> > Simon<br>
> ><br>
> ><br>
> ><br>
> > *From: *<gpfsug-discuss-bounces@spectrumscale.org> on behalf of "<br>
> > marc.caubet@psi.ch" <marc.caubet@psi.ch><br>
> > *Reply to: *"gpfsug-discuss@spectrumscale.org" <<br>
> > gpfsug-discuss@spectrumscale.org><br>
> > *Date: *Thursday, 19 November 2020 at 15:39<br>
> > *To: *"gpfsug-discuss@spectrumscale.org" <gpfsug-discuss@spectrumscale.org<br>
> > ><br>
> > *Subject: *[gpfsug-discuss] Mounting filesystem on top of an existing<br>
> > filesystem<br>
> ><br>
> ><br>
> ><br>
> > Hi,<br>
> ><br>
> ><br>
> ><br>
> > I have a filesystem holding many projects (i.e., mounted under /projects),<br>
> > each project is managed with filesets.<br>
> ><br>
> > I have a new big project which should be placed on a separate filesystem<br>
> > (blocksize, replication policy, etc. will be different, and subprojects of<br>
> > it will be managed with filesets). Ideally, this filesystem should be<br>
> > mounted in /projects/newproject.<br>
> ><br>
> ><br>
> ><br>
> > Technically, mounting a filesystem on top of an existing filesystem should<br>
> > be possible, but, is this discouraged for any reason? How GPFS would behave<br>
> > with that and is there a technical reason for avoiding this setup?<br>
> ><br>
> > Another alternative would be independent mount point + symlink, but I<br>
> > really would prefer to avoid symlinks.<br>
> ><br>
> ><br>
> ><br>
> > Thanks a lot,<br>
> ><br>
> > Marc<br>
> ><br>
> > _________________________________________________________<br>
> > Paul Scherrer Institut<br>
> > High Performance Computing & Emerging Technologies<br>
> > Marc Caubet Serrabou<br>
> > Building/Room: OHSA/014<br>
> ><br>
> > Forschungsstrasse, 111<br>
> ><br>
> > 5232 Villigen PSI<br>
> > Switzerland<br>
> ><br>
> > Telephone: +41 56 310 46 67<br>
> > E-Mail: marc.caubet@psi.ch<br>
> > _______________________________________________<br>
> > gpfsug-discuss mailing list<br>
> > gpfsug-discuss at spectrumscale.org<br>
> > <a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</a><br>
> ><br>
<br>
> _______________________________________________<br>
> gpfsug-discuss mailing list<br>
> gpfsug-discuss at spectrumscale.org<br>
> <a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</a><br>
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<br>
-- <br>
-- Skylar Thompson (skylar2@u.washington.edu)<br>
-- Genome Sciences Department (UW Medicine), System Administrator<br>
-- Foege Building S046, (206)-685-7354<br>
-- Pronouns: He/Him/His<br>
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