Dbspace: system   Shows the size of the main database file. See Pre-defined dbspaces.

Dbspace: translog   Shows the size of the transaction log. See Pre-defined dbspaces.

Dbspace: temporary   Shows the size of the temporary dbspace. See Pre-defined dbspaces.

Disk Reads   Measures the rate at which data is being read from the disk (in kilobytes per second). This value is calculated based on the DiskRead property. See the DiskRead property in Database server properties.

Disk Writes   Measures the rate at which data being written to the disk (in kilobytes per second). This value is calculated based on the DiskWrite property. See the DiskWrite property in Database server properties.