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

[Ryan Novosielski]

> On Nov 19, 2020, at 10:49 AM, Jonathan Buzzard <jonathan.buzzard at strath.ac.uk> wrote:
> 
> On 19/11/2020 15:34, Caubet Serrabou Marc (PSI) wrote:
>> 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.
> 
> This has all the hallmarks of either a Windows admin or a newbie Linux/Unix admin :-)
> 
> Simply put /projects is mounted on top of whatever file system is providing the root file system in the first place LOL.
> 
> Linux/Unix and/or GPFS does not give a monkeys about mounting another file system *ANYWHERE* in it period because there is no other way of doing it.

Some others have said, but I disagree. It wasn’t that long ago that GPFS acted really screwy with systemd because it did something in a way other than Linux expected. As it is now, their devices are not /dev/whatever or server:/wherever like just about every other filesystem type. Not unreasonable to believe it would “act funny” compared to other FS. 

I like GPFS a lot, but this is not one of my favorite characteristics of it.

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