PRIMEQUEST System Disk Mirror for Windows User's Guide V1.0

1.4 Mirror Disk Status

The mirror disks will be in one of the following states.

[Table 1_2: Mirror disk status]

Status	Description
VALID	The data is valid. Data on VALID disks in the same mirror group is always synchronized.
INVALID	The data is invalid. Data on the disk in this status may no longer be synchronized with data on VALID disks in the same mirror group. Disks will be in INVALID status before synchronization copying is initiated or after it is canceled. The synchronization copying is a process to copy data from a VALID disk to other mirror disks in the mirror group in order to set up mirroring or to increase the multiplicity of the mirroring configuration.
COPY	Synchronization copying is in process. To synchronize the data, data from a VALID disk is being copied.
ERROR	An error occurred.

Disks in INVALID or ERROR status are no longer mirrored and become inaccessible. However, if all disks in a mirror group become INVALID or ERROR disks, the last ERROR disk can be accessed.

[Figure 1_9: Disk state transition]

• If the copying process is canceled, the copying will be restarted from the beginning next time. The copying process cannot take over the previous process if it is canceled once.
  

• Resynchronization copying is performed when the system is rebooted in one of the following situations to recover the mirroring state.
  

  • INVALID mirror disks are found when the system is booted.
    

  • The system is rebooted after it failed.
    

• In the resynchronization copying process performed when the system is booted, specific amount of data is copied every 50 milliseconds to reduce the load on the system.