[Pkg-sysvinit-devel] Bug#694379: initscripts: Symlinking /dev/shm to /run/shm makes Oracle Database XE unable to start. Bind mount makes it work.

[Roger Leigh]

On Sun, Dec 09, 2012 at 05:24:50PM +0100, Jozsef Marton wrote:
> Thank you, Roger, for your comments.
> 
> You're right that the test Oracle XE applies is badly broken. See
> details inline your comment below.
> 
> This has not been reported to Oracle as Debian Linux is not a
> supported platform for running their Database product. (I will make
> a try reporting this.)
> 
> Though I understand that dev/shm is an implementation detail, it was
> user for ages and would using bind mount would simplify Debian
> users' life when they intend to use Oracle Database.
> 
> I'm attaching a patch[1] I have tested that makes this behaviour
> configurable in /etc/default/tmpfs leaving symlink as the default
> value. I hope that this can be intergated in Wheezy.

Thanks very much for the patch.  I'll look at merging this, or
something very similar to it--there are some other details which
also need taking care of.

Regarding the actual bug in Oracle, which is basically requiring
the "Mounted on" field to be "/dev/shm", this will break whenever
/dev/shm is a symlink or not the root of a mountpoint.  No
guarantees have ever been made about this, so while we have
exposed the bug by changing to a symlink, the actual bug which
needs fixing is in Oracle.

If you do file a bug with Oracle, which I would strongly
encourage, please could you point them to the fstatvfs(3)
system call, which is what df uses internally.  This will
give them access to the size, free space, filesystem type
etc.  Essentially everything you'd want out of the df
output.  They have the option of using statvfs(2) on
/dev/shm, or fstatvfs(2) on any open file in /dev/shm.
The latter is advisable, due to /dev/shm being an
implementation detail; they should be using shm_open(3) in
order to open files here, which would make fstatvfs(2)
the preferred choice.


Regards,
Roger

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