Dell PowerVault MD3200 Owner's Manual - Page 114

Hot Spare Operation When a physical disk fails, the virtual disk automatically rebuilds using an available hot spare. When a replacement physical disk is installed, data from the hot spare is copied back to the replacement physical disk. This function is called copy back. By default, the RAID controller module automatically configures the number and type of hot spares based on the number and capacity of physical disks in your system. A hot spare may have the following states: • A standby hot spare is a physical disk that has been assigned as a hot spare and is available to take over for any failed physical disk. • An in-use hot spare is a physical disk that has been assigned as a hot spare and is currently replacing a failed physical disk. Hot Spare Drive Protection You can use a hot spare physical disk for additional data protection from physical disk failures that occur in a RAID Level 1, or RAID Level 5 disk group. If the hot spare physical disk is available when a physical disk fails, the RAID controller module uses redundancy data to reconstruct the data from the failed physical disk to the hot spare physical disk. When you have physically replaced the failed physical disk, a copyback operation occurs from the hot spare physical disk to the replaced physical disk. If there are secure disk groups and security capable disk groups in the storage array, the hot spare physical disk must match the security capability of the disk group. For example, a non-security capable physical disk cannot be used as a hot spare for a secure disk group. NOTE: For a security capable disk group, security capable hot spare physical disks are preferred. If security capable physical disks are not available, non-security capable physical disks may be used as hot spare physical disks. To ensure that the disk group is retained as security capable, the non-security capable hot spare physical disk must be replaced with a security capable physical disk. If you select a security capable physical disk as hot spare for a non-secure disk group, a dialog box appears indicating that a security capable physical disk is being used as a hot spare for a non-secure disk group. The availability of enclosure loss protection for a disk group depends on the location of the physical disks that comprise the disk group. The enclosure loss protection might be lost because of a failed physical disk and location of the 114 Configuration: Disk Groups and Virtual Disks