Why does deleting recordings not always free up space?

Why does deleting recordings not always free up space?

The DVR Express Core file system does not support recording to multiple blocks of free space. De-fragmentation of the file system is not supported as it is time consuming and risks loss of data. The scratch file created prior to recording always uses the largest continuous block of free space on the drive set.

For example, suppose five recording of varying length are created on a drive set that was initially empty (see figure below). Observe the largest continuous block of available space is at the end of the drive set. A sixth recording could be created that uses the remaining 20%.
 


Now suppose the files #2 and #4 are deleted (see figure below). Observe the total amount of free space increases to 60%, however the maximum new file size is limited to 30% because the largest continuous block of free space is only 30%.


To use the remaining 60%, files #3 and #5 would need to be exported (if necessary) and deleted.
    • Related Articles

    • How to Free up Space on a DVR

      When a drive set becomes full, recording files must be deleted in order to make space for new recordings. If the video stored in one or more recording files needs to be preserved for future use, it can be offloaded to a portable backup file (.mdf). ...
    • Where is DVR Express Core video data stored when making recordings in Streams 7?

      Each 'scene' in Streams 7 correlates with a recording file kept on the DVR's recording media. This means that the Streams 7 video library file (*.vl) doesn't contain the image data. By default, when you delete a scene, the corresponding reocrding ...
    • How to Check if Camera Data Rate is too High Using Storage Manager

      This article will help verify if the data rate of the attached cameras is too high for the VidIO module drive set installed in your DVR Express CORE 2 recorder. Before starting make sure your DVR is set up properly, the attached cameras are ...
    • Is it Possible to Use Consumer SSD Drives on a Core and Core 2?

      DVR Express Core 2 Consumer SSDs will not be recognized by Core 2 devices. VidIO Drive Modules are the only storage media that will function with a DVR Express Core 2 device. These must be purchased from IO Industries. DVR Express Core Supports ...
    • DVR Express Core Timing Information

      Resolution/Precision The Core DVRs apply timestamps to incoming frames regardless of whether PC Time is being used, or another timing reference (e.g. IRIG-B or GPS etc.).  Regardless of the source, the timestamps have the same resolution/precision.  ...