In RAID-Z, the width of the stripe can vary. For a small block (such as would hold 512 bytes or less of file data), the stripe will be 1 data block and either 1 or 2 parity blocks. So a full-stripe write will simply look like either mirroring (RAIDZ1) or mirror plus one additional ECC block (RAIDZ2). In either case, there aren't any "unused" blocks written to disk.
See <http://cvs.opensolaris.org/source/xref/on/usr/src/uts/common/fs/zfs/vdev_raidz.c>. You can see this logic in vdev_raidz_map_alloc(). This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
