Drive Detection & Use:
- The Nx Witness Server application, once installed upon a computing device, detects and analyzes available storage during the setup process.
- Nx Witness will utilize all drives in a Server and writes concurrently to all enabled drives, so the more drives you have in a Server the less throughput you'll see on any individual drive.
- Nx Witness will not allow recording to drives that are less than 10% the size of the largest drive in the system (e.g. an SD Card or USB Flash drive). For example, if a user has 10 TB NAS registered at some server all other drives with total space less than 1 TB will be disabled for recording at this particular server. This is done to ensure a correct write-ratio calculation and to improve overall system stability.
- External storage drives can also be assigned via the Nx Witness client. Storage options include local storage to the HDDs available on the server computer, Direct-Attached Storage (DAS), and Network-Attached Storage (NAS).
General Nx Witness Write-to-Archive Process:
- IP Video camera streams are detected and captured by the Nx Witness Media Server and stored in RAM.
- The Nx Witness Server writes captured IP video in RAM to available storage (internal hard drives, DAS, or NAS) once per minute..
- All suitable drives are written concurrently and according to a ratio the system calculates for their size. So, for example, if a single server has multiple sized hard drives Nx Witness will fill up each hard drive at the same rate to ensure that no single drive's system bus gets overloaded.
- Nx Witness keeps some free space at every drive so that performance is not affected. You can find more details by reading our article about adjusting reserved disk space.
- When any storage drive (e.g., X) is full, Nx Witness will begin to delete recorded video starting with the earliest/oldest video on the server across all drives until there's enough space on the drive to record a given amount data. As a result, a solid timeline is guaranteed.
- Since 2.6 version Nx Witness prevents recording onto the system drive if there's any other storage drive installed on the server which meets the minimum requirements and is at least 5 times larger than system disk.
- User can not manually modify the archive (delete/add/etc.) using Nx Software
How is hard disk failure managed?
If a single drive in a multiple drive system fails the Nx Witness system will do the following:
- continue writing to all available drives
- create a notification in the notifications panel that a hard drive failure has occurred
- rebuild the archive index after the Media Server is restarted
- If Failover-on-Hard-Drive-Failure is enabled the cameras writing to this drive will be moved to a designated Failover server (starting in v4.0).
If you have any questions related to this topic or you want to share your experience with other community members or our team, please visit and engage in our support community or reach out to your local reseller.