A method, wherein a storage system comprises available disks, ∘ wherein the available disks are grouped into G available disk groups DG i, wherein i is an integer from 1 to G, G is an integer, G is not less than 2, ∘ wherein a quantity of disks in the available disk group DG i is N i, ∘ wherein a capacity of each disk Di in the DG i is CD i, and a capacity CD x of each disk D x in a DG x is greater than a capacity CD x+1 of each disk D x+1 in a DG x+1, x is an integer, and x is an integer from 1 to G-1, ∘ wherein a stripe length that can be effectively configured in the storage system is [r, z], wherein r and z are positive integers and z is greater than r, wherein a stripe is formed by a plurality of stripe units distributed in parallel into a plurality of disks of the G available disk groups when data are to be stored; and the method comprises: • obtaining, by a management device, a candidate stripe length LORIG y, wherein a value of y is an integer in the stripe length from r to z that can be effectively configured, and LORIG y =y (step 601); and • calculating, by the management device, an available capacity that is of the storage system and that corresponds to a stripe having the candidate stripe length LORIG y (step 602), wherein the method further comprises: • determining, by the management device based on an available capacity that is of the storage system and that corresponds to each stripe having a candidate stripe length from LORIG r to LORIG z, a candidate stripe length LORIG P corresponding to a maximum value of available capacities of the storage system, wherein a value of P is an integer in r to z, • configuring, by the management device, a stripe length of the storage system as LORIG P. ∘ wherein the available disks are grouped into G available disk groups DG i, wherein i is an integer from 1 to G, G is an integer, G is not less than 2, ∘ wherein a quantity of disks in the available disk group DG i is N i, ∘ wherein a capacity of each disk Di in the DG i is CD i, and a capacity CD x of each disk D x in a DG x is greater than a capacity CD x+1 of each disk D x+1 in a DG x+1, x is an integer, and x is an integer from 1 to G-1, ∘ wherein a stripe length that can be effectively configured in the storage system is [r, z], wherein r and z are positive integers and z is greater than r, wherein a stripe is formed by a plurality of stripe units distributed in parallel into a plurality of disks of the G available disk groups when data are to be stored; and • obtaining, by a management device, a candidate stripe length LORIG y, wherein a value of y is an integer in the stripe length from r to z that can be effectively configured, and LORIG y =y (step 601); and • calculating, by the management device, an available capacity that is of the storage system and that corresponds to a stripe having the candidate stripe length LORIG y (step 602), • determining, by the management device based on an available capacity that is of the storage system and that corresponds to each stripe having a candidate stripe length from LORIG r to LORIG z, a candidate stripe length LORIG P corresponding to a maximum value of available capacities of the storage system, wherein a value of P is an integer in r to z, • configuring, by the management device, a stripe length of the storage system as LORIG P.