The Storage History provides an overview of past storage utilization on the Storage Center.
Total Disk Space - This is the amount of raw disk space available.
Low Space Threshold - This is the threshold at which the Storage Center will display a Low Space warning message. The threshold defaults to 10% of the total disk space available.
Allocated Disk Space - This is the amount of disk space that has been allocated for use by volumes and replays.
Used Disk Space - This is the amount of disk space used by volumes and replays.
When disk drives are managed by the Storage Center, they are placed within a disk folder, which is simply a logical grouping of physical drives. Disk folders may contain a mixture of drive types, capacities, and speeds. The total capacity of the disk folder is the sum of the capacities of the drives within the folder. Disk folders may also contain disk drives which are specified as hot spares. These hot spare drives are reserved for use as replacement drives in the event another disk in the disk folder fails. Since the space on these hot spares is never used until another drive fails, their capacity is not included in the total capacity for the disk folder.
The Storage Center allocates disk space from a disk folder for volume and replay use as needed based upon the configurations and IO patterns of each volume.
As the Storage Center approaches the end of the disk space available within the disk folder, you will be notified of the possibility that you could run out of space.
This notification indicates that you are in a Space Low state. The notification occurs when the Disk Space Available value falls below the Storage Alert Threshold (10%).