On Apr 29, 2008 09:05 -0700, Kilian CAVALOTTI wrote: > On Tuesday 29 April 2008 07:53:01 am Brian J. Murrell wrote: > > Unless you are using Lustre for your root and/or usr filesystem > > and/or for swap, Lustre should not hang a machine completely. > > I was precisely wondering if it was possible to use a file residing on a > Lustre filesystem as a swap file. I tried the basic steps without any > success. > > On a regular ext3 fs, no problem: > > /tmp # dd if=/dev/zero of=./swapfile bs=1024 count=1024 > 10240+0 records in > 10240+0 records out > /tmp # mkswap ./swapfile > Setting up swapspace version 1, size = 104853 kB > /tmp # swapon -a ./swapfile > /tmp # swapon -s > Filename Type Size Used Priority > /dev/sda3 partition 4096564 204 -1 > /tmp/swapfile file 102392 0 -2 > > But on a Lustre mount: > > # 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
Note that in 1.6.4+ there is an interface to export a block device more directly from Lustre instead of using the loopback driver on top of the client filesystem. This is the "llite_loop" module and is configured like: lctl blockdev_attach {loopback_filename} {blockdev_filename} where {loopback_filename} is the file that should be turned into a block device (it can be sparse if desired) and {blockdev_filename} is the full filename that the new block device should be created at. To clean up the device use: lctl blockdev_detach {blockdev_filename} Note that using this block device for swap hasn't been very successful in our testing so far, but we also haven't done a great deal of real world testing only "allocate a ton of RAM and dirty it all as fast as possible", which isn't a very realistic usage. Feedback would be welcome. Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. _______________________________________________ Lustre-discuss mailing list Lustre-discuss@lists.lustre.org http://lists.lustre.org/mailman/listinfo/lustre-discuss