Common hot spare for multiple RAID groups

A storage system, comprising:

• a first RAID group comprising a first plurality of physical drives configured in a first RAID level, the first plurality of physical drives comprising at least a first physical drive and a second physical drive;
• a second RAID group comprising a second plurality of physical drives configured in a second RAID level that is different than the first RAID level, the second plurality of physical drives comprising at least a third physical drive and a fourth physical drive;
• and,
• a single common dedicated hot spare physical drive having a first portion of storage space and a second portion of storage space, the first portion of storage space of the common dedicated hot spare physical drive configured to operate, in the event of a failure of the first physical drive, as a first dedicated hot spare to the first RAID group, and the second portion of storage space of the common dedicated hot spare physical drive configured to operate, in the event of a failure of the third physical drive, as a second dedicated hot spare to the second RAID group, the common dedicated hot spare physical drive not used as part of said first RAID group and not used as part of said second RAID group,
• wherein the first RAID group is operable to rebuild the first physical drive of the first RAID group in the first portion of the storage space of the common dedicated hot spare physical drive, and
• wherein the second RAID group is operable to rebuild the third physical drive of the second RAID group in the second portion of the storage space of the common dedicated hot spare physical drive.

A non-transitory computer readable medium having

• instructions stored thereon for operating a redundant array of independent disks (RAID) storage system that, when executed by a computer, at least instruct the computer to:
• group a first plurality of physical drives into a first RAID group in a first RAID level, wherein the first plurality of physical drives comprises at least a first physical drive and a second physical drive;
• group a second plurality of physical drives into a second RAID group in a second RAID level that is different than the first RAID level, wherein the second plurality of physical drives comprises at least a third physical drive and a fourth physical drive;
• allocate a first portion of storage space of a single common dedicated hot spare physical drive to operate, in the event of a failure of the first physical drive, as a first dedicated hot spare to the first RAID group, the common dedicated hot spare physical drive not used as part of said first RAID group and not used as part of said second RAID group;
• and,
• allocate a second portion of storage space of the common dedicated hot spare physical drive to operate, in the event of a failure of the third physical drive, as a second dedicated hot spare to the second RAID group;
• rebuild the first physical drive of the first RAID group in the first portion of the storage space of the common dedicated hot spare physical drive;
• and
• rebuild the third physical drive of the second RAID group in the second portion of the storage space of the common dedicated hot spare physical drive.