Re: Partial checkout builds

[Krzysztof Cieniuch]

Luke Shumaker wrote:
> I would suggest trying UnionFS (supported either natively, or via FUSE
> on most *NIXen).  What you do is mount /release/src under /local/src,
> with /local/src/ on top and /release/src on bottom.  UnionFS first
> checks if a file exists on at the top layer, and keeps checking the next
> layer until it finds the file, or goes through all the layers.
>
> top:    /local/src:     util.h  m1.cc
> bottom: /release/src:   util.h  m1.cc   m2.cc
>
> Depending on which kernel you're on, you can either do the mount directly in 
> /local/src,
> or you may have to create a separate directory (as you do in Linux).
>
> on Linux (via FUSE) the command to mount is:
> unionfs-fuse -o cow /local/src/=RW:/release/src/=RO /build/src
>
> on FreeBSD the command is:
> Native:
> mount -o union /release/src /local/src
> FUSE:
> mount_unionfs -o below /release/src /local/src
>
> I hope this helps!
>
> ~ LukeShu
>
> O
This would be perfect since it would also work for Java builds (we have 
mixed projects Java and c++)
and is user space tool so could be used by developers ... but :-((( 
unfortunately FUSE is not supported
on Solaris (our primary target OS) and HP-UX ia64.
(There is a port of bsd FUSE to open solaris but it looks like it is 
early stage and I won't be allowed
to install some experimental kernel modules on build servers.)

I was googling for few hours for union mount, union filesystem, overlay 
filesystem, overlay directories
and it looks that this feature is supported mainly on Linux and BSD like 
systems so I'm stuck with my preload hack.

On the other hand FUSE and unionfs-fuse seem like an exact match so I 
try different approach as well:
create FS Gateway server that would on demand create unions and make 
them available via NFS

Thanks for pointing unionfs as possible solution.

Chris