Disk space is allocated by the system in 512-byte sectors. An integral number of sectors are grouped together to form a logical block. VxFS supports logical block sizes of 1024, 2048, 4096, and 8192 bytes. The default block size for file systems less than one terabyte is 1024 bytes. The block size may be specified as an argument to the
mkfs utility and may vary between VxFS file systems mounted on the same system. VxFS allocates disk space to files in extents. An extent is a set of contiguous blocks.