Re: the 'why' of pseudofs

[Bill Hacker <wbh@xxxxxxxxxxxxx>]

Jost Tobias Springenberg wrote:
> I do not want to sound offensive here but I don't get the point of this discussion at all.
> What exactly is wrong with null mounts and / or the way PFS work ?
>
> If you want to have seperate partitions instead of PFS, thats perfectly fine, nobody 
> forces you to use PFS everywhere. In fact It might be very reasonable to keep data from home 
> directories seperated from other data or the like.
>
> Regarding null_mounts, I do not see any programm that might not be able to work with them.
> And User failure is also not a real issue here, as those mounts can be secified in fstab as well as 
> any other mount and the concept is not that hard to grasp.
> Regards,
> 	Tobi

No offense taken (nor meant).

And thanks for the input - taken on-board.

For someone who has spent much of the last two years experimenting with 
Gfarm, Gluster, Ceph, DFarm, Chiron, AFS, Coda, (AND NOT ZFS) etc ad 
nauseum..

. .even (most reluctantly) having to endure Linux lib-version-Hell to be 
able to test several of those too-often 'fuse' dependent critters *at all*,

. . it isn't the *concept* that is hard to grasp.

It's the "gotcha's" I'm trying to ring-fence.

;-)

And, to seek better sync between docs and methods.

EX:

man (5) hammer has an example of creating and mounting /home/pfs/master, 
/home/pfs/slave. Then /home/master and 'home/slave for mirror-copy >> 
mirror-stream.

But the 2.3.0 DEVELOPMENT iso had already mounted /home (/usr, /var, 
etc) .... as PFS....

By the time I had sorted a new non-pfs mount directly off '/' and got 
all the mirror-stream stuff working, a simple reboot blew way the 
now-multiply-recursively-mounted, BFBI privs and ownership FUBAER'ed, 
and overly aggressive pfs-destroy'ed,  '/home' altogether

. .. *before* I had remapped all console messages to a log file.. so I 
saw it complain - but had no details.

Recoverable? Maybe, maybe not.

But testing calls for a complete re-install to a different formula 
anyway, so....

'Essayons'

Regards,

Bill