Subject: Re: objdirs and readonly /usr/src
To: Stephen Ma <>
From: Dick Davies <>
List: current-users
Date: 02/21/2004 20:05:45
Stephen Ma wrote:
> Dick> Hi. Bit stuck.  I mount /usr/src readonly over NFS to my current
> Dick> box.  When I try to build tools, I get this error:
>> cc  -O -o nbmake *.o
>> #    objdir  /usr/obj/tools
>> ln: obj: Read-only file system
> Dick> Which I assume is because can't make symlinks in
> Dick> /usr/src.
> I'm building with the objdir set by the "-M" option to
> ("MAKEOBJDIR" var). When using that, the build doesn't seem to need to
> symlink from the source.

Thanks that'll do me :)

> An alternative, which I used before appeared on scene, was to
> use the union fs, which allows you to mount a read-write layer on top
> of a read-only fs. At the time, however, union sometimes caused
> build processes to hang permanently - dunno if that's been fixed. And
> I don't know if union works properly on top of NFS mounted fs.

Don't know how much disk that'll take, but my preferred alternative
would be rsync -
it costs a few hundred Mb, but at least you have a local
source tree if need be. I've lost the NFS server before and had to 
pressgang my laptop into service as a wireless gateway -
it was slowed down by having to fetch sources for a custom kernel build.