[users at i-scream] CPAN Sys::Filesystem on diskless AIX

Jens Rehsack rehsack at cpan.org
Fri Aug 24 10:00:43 BST 2012

On 24.08.2012 10:41, David Lee wrote:
> Jens,


> [A quick re-introduction.  About two years ago (Oct 2010) we were in
> contact about particular aspects of "Sys::Filesystem".]
> I've now got a bug report for the ::Aix module.  But I should first
> point out that I'm not an AIX expert at all, by any stretch of the
> imagination.
> A new AIX machine-cluster at our site is based on diskless nodes,
> whereas our previous AIX systems have all had local disk.
> I put an existing perl application, that uses "Sys::Filesystem", onto
> this new cluster and we got some strange error messages concerning
> "lsvg".  We quickly tracked this down to module "Sys::Filesystem::Aix".
> The module executes:
>    /usr/sbin/lsvg -Ll `/usr/sbin/lsvg -Lo`
> This is fine on disk-based systems.  The embedded back-tick command
> produces one or more lines of genuine output; the surrounding command
> (with the "-Ll ....") can then process these lines.
> But on a diskless system the embedded back-tick command produces zero
> lines of output; the surrounding command expects to see one or more
> lines, so complains:
> ----
> 0516-992 lsvg: Illegal combination of command line options.
> Usage: lsvg [-o] [[-L] -n PVname]
>        lsvg [-L] [-i] [-P] [-m] [-M | -l | -p] VGname...
> Lists the characteristics of a volume group.
> ----
> Could you investigate this, please?

I had a defect on my infrastructure machine storing my repository. I'll
try to get it online again as soon as possible. Please don't hesitate to
bug me again when I don't react soon.

As I don't have physical access on any AIX box at the moment, it could
take a bit longer to find an appropriate solution. I'm still unlucky
with the implementation on AIX.

My favourite implementation uses mntctl as you can see in
line 745..1021.

I'm not sure whether I can access mntctl from Perl, if XS parts for
Sys::Filesystem might be interesting, ...

Please don't hesitate to write tdb at i-scream.org and/or
users at i-scream.org and ask for a roadmap to release next version of
libstatgrab (this can be used in Unix::Statgrab and therefore in
Sys::Filesystem, too - when available).

> Local impact and local workaround:
> It so happens that our local impact of this bug is small at present. Our
> application would like to determine whether a filename is truly local or
> is NFS-mounted.  That is why it is calling "Sys::Filesystem". If it is
> NFS, it will attempt to process it in a slightly different way.  Our
> local workaround, which is OK for the moment, is simply to avoid
> "Sys::Filesystem" altogether on this platform and assume all files are
> truly local.

Well, without local disks, the assumption should be, none truly local,
shouldn't it?

> I hope that is enough information to outline the problem.  If you need
> anything else for it, let me know.  (If it gets into details of AIX,
> I'll probably pull a local AIX person into this discussion!)
> -- David Lee

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