Spare storage allocation and selection order control

A data storage system comprising:

• processing circuitry;
• a set of data storage drives;
• and
• memory coupled to the processing circuitry and the data storage drives, the memory storing instructions, wherein the instructions, when executed by the processing circuitry, cause the processing circuitry to:
• within the set of data storage drives, identify a prime data storage drive having a largest total capacity of the data storage drives in the set;
• allocate virtual RAID groups from the set of data storage drives by, for each virtual RAID group, causing the processing circuitry to:
• allocate the number of storage slices that is required by each virtual RAID group to the virtual RAID group, and
• in response to one of the storage slices allocated to the virtual RAID group having been allocated from the prime storage drive, allocate a spare storage slice to the virtual RAID group.

A computer program product including a non-transitory computer readable medium having instructions stored thereon, wherein the instructions, when executed on processing circuitry, cause the processing circuitry to perform steps including:

• within a set of data storage drives, identifying a prime data storage drive having a largest total capacity of the data storage drives in the set;
• allocating virtual RAID groups from the set of data storage drives by, for each virtual RAID group:
• allocating the number of storage slices that is required by each virtual RAID group to the virtual RAID group, and
• in response to one of the storage slices allocated to the virtual RAID group having been allocated from the prime storage drive, allocating a spare storage slice to the virtual RAID group.