On Tue, Apr 29, 2008 at 04:27:42PM -0400, Brian J. Murrell wrote: >On Tue, 2008-04-29 at 09:05 -0700, Kilian CAVALOTTI wrote: >> I was precisely wondering if it was possible to use a file residing on a >> Lustre filesystem as a swap file. >There certainly has been some historic use and testing of swap on >Lustre. I'm not sure what it's current state is TBH. The last bug in >bugzilla I can find about swap and Lustre is bug 5794/5749/5188 filed >over two years ago (however updated just recently) in reference to some >of our regression testing we do with swap on Lustre. > >It seems the final outcome is that it has been flagged (just today in >fact) as a 1.6.6 blocker. The timing is absolutely uncanny! > >> # cd /scratch >> /scratch # grep /scratch /proc/mounts >> [EMAIL PROTECTED]:/scratch /scratch lustre rw 0 0 >> /scratch # dd if=/dev/zero of=./swapfile bs=1024 count=1024 >> 10240+0 records in >> 10240+0 records out >> /scratch # mkswap ./swapfile >> Setting up swapspace version 1, size = 104853 kB >> /scratch # swapon -a ./swapfile >> swapon: ./swapfile: Invalid argument >> >> Is that expected? > >I would think not, no. There is some reference in bug 5188 that we only >test it for "real/remote OSTs" and "non-TCP" interconnects. I wonder if >either of those match your situation. You might file a bug about it, >including the usual data -- syslog from the client you did the swapon on >for example. A (-1) debug log from the client right at the time of the >swapon would probably be useful.
when doing the 'swapon' if you look in dmesg you should see: kernel: swapon: swapfile has holes even though the file on Lustre isn't sparse. I was looking into this last week, and I think this message is because Lustre (at least up to 1.6.4.3) doesn't appear to implement bmap() -> lustre/llite/rw26.c:289: .bmap = NULL and the swapfile code in RedHat kernels and 2.6.23 mm/swapfile.c setup_swap_extents() expects bmap() to be present, and assumes the file is sparse otherwise :-/ we too are very interested in swap on Lustre using o2ib, so I'm happy to hear it'll be in 1.6.6. cheers, robin _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
