Disk Space Management
The data segments recorded by the Hawks are stored as a first level of storage on the Hawk disks. During acquisition, it is possible to see how much space is left on the Hawks (1), and how much recording time (based on disk space, number of channels, and acquisition sample rate) is left (2). Note that this indicator will turn orange and then red as we go above warning and alarm threshold.
Once authorised, if the Acquisition system is connected to a Hercules (the HGL Archiving system), the data will automatically be archived onto the Hercules, which would be the second level of storage.
On the acquisition system, the disk controller application (generally installed on the Hawk Controller machine) continuously monitors the disk space on the Hawk(s). When the used space is above a certain level (configurable), it will hunt in the database for archived files (i.e. files which are now also on the Hercules), and delete them, starting with the oldest files. It will continue to do so until it runs out of files to delete (the remaining files have not been archived yet), or the occupied space has dropped below a certain level (which is also configurable).
In automatic mode, this ensures that the user can run indefinitely (endurance testing), as long as rate of transfer of the files to the Hercules is equal or greater than the acquisition throughput.
In manual authorisation mode, the system will stop writing by itself once the Hawk disks are full above a given threshold. The threshold is configurable in the preferences:
- Stop write threshold: specified as duration, this is the minimum remaining disk space required. Below this level, the system stops writing automatically.
- Alarm threshold: specified as duration, when remaining disk space is below this threshold, the indicator turns red.
- Warning threshold: specified as duration, when remaining disk space is below this threshold, the indicator turns orange.