Slow drive detection

A storage device system comprising:

• a plurality of storage drives;
• and
• a storage controller configured to:
• dynamically create a first storage drive peer group including at least two of the plurality of storage drives, the peer group selected from the plurality of storage drives based on a shared characteristic including drive type, drive model, I/O pattern, or RAID group membership of drives in the peer group, the peer group being a subset of the plurality of storage drives;
• compare performance statistics of the storage drives in the first storage drive peer group;
• select an outlier storage drive of the storage drive peer group for active measurement based on the comparison of the performance statistics;
• and
• dynamically create a second storage drive peer group including at least two of the plurality of storage drives, the second peer group selected from the plurality of storage drives based on a shared characteristic different than the shared characteristic of the first peer group, the shared characteristic including drive type, drive model, I/O pattern, or RAID group membership of drives in the second peer group, the second peer group being a second subset of the plurality of storage drives.

A computer-readable storage medium encoding a computer program for executing a computer process on a computer system, the computer process comprising:

• dynamically creating a first storage drive peer group including a plurality of storage drives selected from a group of drives in a data storage system, the first peer group selected based on a shared characteristic including drive type, drive model, I/O pattern, or RAID group membership of drives in the first peer group, the first peer group being a subset of the group of drives;
• comparing performance statistics of the plurality of storage drives of the first storage drive peer group;
• selecting an outlier storage drive of the first storage drive peer group based on the comparison of the performance statistics;
• and
• dynamically creating a second storage drive peer group from the group of drives, the second peer group including a second plurality of storage drives selected from the group of drives and selected based on a shared characteristic different than the shared characteristic of the first peer group, the shared characteristic including drive type, drive model, I/O pattern, or RAID group membership of drives in the second peer group, the second peer group being a second subset of the group of drives.