Silicon Graphics InfiniteStorage 4000 Series, Configuring And Maintaining, Page: 51 / 276

Chapter 3: Configuration Concepts 39
Figure 1 Drive Drawer with Drives
The total number of drives in a storage array depends on the model of the controller
tray or controller-drive tray and the capacity of the drives. The following table lists,
by controller tray or controller-drive tray model and drive tray capacity, the maximum
number of drives in a storage array.
NOTE
A maximum of seven drive trays can be on a channel when mixing 14-slot
drive trays and 16-slot drive trays.
The maximum capacity in a storage array depends on the number of the drives in the
storage array and the capacity of each drive in the storage array. The following table
lists the maximum storage for each controller model based on the capacity of the
drives.
Hot Spare
Drives
NOTE
Hot spare drives works only on storage arrays configured to use volume
groups.
A hot spare is a drive that acts as a standby in the event that a drive containing data
fails. The hot spare is a drive that has not been assigned to a particular volume group
and, as such, can be used in any volume group. You can use the hot spare feature with
RAID Level 1, RAID Level 3, RAID Level 5, or RAID Level 6. If a drive in a volume
group fails, the controllers automatically replace the failed drive with a hot spare. The
controllers use redundancy data to reconstruct the data from the failed drive onto the
hot spare. To be most effective, the drive that you assign as a hot spare must have a
capacity equal to or greater than the capacity of the largest drive in the storage array.