man lvcreate - Am I blind or there is no description for "sS" ? (I can't find on redhat manual pages as well)
-L, --size LogicalVolumeSize[bBsSkKmMgGtTpPeE] Gives the size to allocate for the new logical volume. A size suffix of K for kilobytes, M for megabytes, G for gigabytes, T for terabytes, P for petabytes or E for exabytes is optional. Default unit is megabytes.