On Jun 08, 2007 15:38 -0600, Lee Ward wrote: > > Other notes - in about Lustre 1.6.2 it will be possible to use the FIEMAP > > ioctl to help in efficiently preallocating space in the file for the > > ADIO_FCNTL_SET_DISKSPACE fcntl. That will avoid the need to read the > > whole file, and instead just get a list of allocated and unallocated > > extents back. > > There are no Lustre ioctl's of any kind implemented in liblustre. The > Lustre client driver takes them but just returns an error. Maybe my info > dated here? I admit it's been a coupe of months since I last looked at > this.
Actually, it is possible for a catamount client to use llapi_file_create() to specify striping on a newly-created file, and that internally calls the ioctl that the Lustre ADIO driver as presented here calls explicitly. > The data sieve can be engaged via an MPI hint and executed at an extant, > higher, layer if I recall correctly. I agree - having small IO handled via sieving or collective IO is much better than trying to make small IOs marginally more efficient. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc. _______________________________________________ Lustre-discuss mailing list [email protected] https://mail.clusterfs.com/mailman/listinfo/lustre-discuss
