On Jul 15, 2009 14:24 -0700, Sage Weil wrote: > A few Ceph ioctls for getting and setting file layout (striping) > parameters. > + > +#define CEPH_IOC_GET_LAYOUT _IOR(CEPH_IOCTL_MAGIC, 1, struct ceph_file_layout) > +#define CEPH_IOC_SET_LAYOUT _IOW(CEPH_IOCTL_MAGIC, 2, struct ceph_file_layout) I've been trying to get some steam behind a more common interface for backing up and restoring file layout information, using virtual xattrs. This will allow tar/rsync/etc to back up the layout xattr and then restore it (preferrably before the data is written) to the target, so that any user-specified file layout is preserved. I'm thinking of using simple ASCII key=value pairs to store basic layout information like chunk size, stripe count, mirror count, RAID type, etc. Some of them may not be applicable/usable by all filesystems, but having a handful of "well known" keys and values for a common xattr name would at least be better than what we have now (which is nothing). Something like (not necessarily a firm proposal yet): trusted.common_layout: chunk_bytes=65536 stripe_count=32 mirror_count=3 raid_type=1+0 Is this something you would be interested to pursue? I've also discussed this with Panasas, and they had some interest in this as well. Any GPFS developers watching? Cheers, Andreas -- Andreas Dilger Sr. Staff Engineer, Lustre Group Sun Microsystems of Canada, Inc. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
