[lustre-discuss] Apache via NFS via Lustre

[John Dubinski]

Hi,

I'm wondering if there are any developments on this front. 

We also NFS export some lustre filesystems from a client to an apache server so that users can link to their large datasets on their personal websites.  This has been working for years for us using lustre 1.8.

We recently built some new systems using lustre 2.5.3 and now this functionality is broken in the same way that Eric describes - symlinks to directories and files on the lustre filesystem are denied by the apache server.  This doesn't seem to be due to our apache configuration since symlinks to files and directories in ordinary (non-lustre) nfs-mounted filesystems work.  Also the nfs-exported filesystems behave normally - you can copy files in, as well as create and delete files as you wish.
The only problems arise in relation to apache access.

We've also noticed that whenever the forbidden access messages comes up in the browser /var/log/messages on the lustre client spits out this error consistently:

Mar  8 19:53:14 nuexport02 kernel: LustreError: 2626:0:(mdc_locks.c:918:mdc_enqueue()) ldlm_cli_enqueue: -13

This appears to be related to file locking looking at the code...

We have also built a test apache server with lustre client modules that directly mount our lustre filesystems.  symlinks to the directories in the lustre fs within /var/www/html similarly return the forbidden access message with the above mdc_locks error.

We're running CentOS 6 with lustre 2.5.3 on the client and server side.  To repeat, direct client mounts of the lustre filesystems behave normally as well as nfs-exported mounts.  Only apache access to symlinks of files on a lustre filesystem give trouble.

Are there any special nfs export flags that can be set to help in /etc/exports?

Thanks for any help or insight!  

Regards,

John

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John Dubinski
Canadian Institute for Theoretical Astrophysics
University of Toronto    phone:  416-946-7290
60 St. George St.        fax:    416-946-7287
Toronto, Ontario         e-mail: dubinski at cita.utoronto.ca
CANADA M5S 3H8           url:    www.cita.utoronto.ca