On Tue, Nov 05, 2013 at 04:34:47PM +0100, Honza Horak wrote:
On 11/01/2013 08:28 PM, Toshio Kuratomi wrote:
>A straw poll was taken about the filesystem location of SCLs. A few FPC
>members were willing to use /opt but others were heavily opposed to it.
>Everyone was okay with using /usr/scl (or the plural form /usr/scls). So
>I think that needs to become the scl root dir (is that the right term?) for
>Fedora.
>
>FPC was okay with the idea that third parties might use /usr/scl as well.
>I didn't bring this up at the meeting but one thing that influences me on
>this is that scls are inherently rpm managed and therefore mixing both our
>scls with third party scls does not seem like the same vendor-OS problem
>that /opt was designed to fix.
I feel the need to add my POV about choosing /usr/scl for SCL prefix.
FHS states: "/usr is the second major section of the filesystem. /usr
is shareable, read-only data. That means that /usr should be
shareable between various FHS-compliant hosts and must not be written
to. Any information that is host-specific or varies with time is
stored elsewhere." [1]
That seems to me like a no-go for having /usr/scl as a prefix for
SCLs, because there surely are packages that need to write some
files, probably not only databases. So I'd also vote for /opt since
there are no such requirements.
[1]
http://www.pathname.com/fhs/pub/fhs-2.3.html#THEUSRHIERARCHY
Although I favor /opt, this is not one of the reasons. Our interpretation
of /opt is that we also cannot depend on it being read-write and
host-specific. It looks like fhs developed /opt to be a vendor-friendly
version of /usr. Therefore it is also read-only and shareable. The
reasoning stems from FHS's decision to separate read-write and host-specific
information from /opt:
"""
Package files that are variable (change in normal operation) must be
installed in /var/opt. See the section on /var/opt for more information.
Host-specific configuration files must be installed in /etc/opt. See the
section on /etc for more information.
"""
http://www.pathname.com/fhs/pub/fhs-2.3.html#OPTADDONAPPLICATIONSOFTWAREP...
As stated in my Filesystem Location Part 2 email:
https://lists.fedoraproject.org/pipermail/packaging/2013-November/009717....
"we also noted that no matter whether /usr or /opt was used, config files
would still need to be placed somewhere under /etc and state files somewhere
under /var."
-Toshio