How Does DW Spectrum IPVMS Manage Storage?
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Affected Roles: Owner, Administrator
Related Digital Watchdog VMS Apps: DW Spectrum IPVMS
Last Edit: February 22, 2024
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Supported/Affected Devices:
- DW Blackjack® Server Series
- DW Blackjack® NAS Series
Drive Detection & Use
- Once installed onto a computer, the DW Spectrum Server application detects and analyzes available storage during the setup process.
- DW Spectrum will utilize all drives that are installed within a Server and write concurrently to all enabled drives. As a result, the more drives that are in a Server, the less throughput you will see on any individual drive as the work will be shared across the enabled drives.
- DW Spectrum will not record archive files 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 a 10 TB NAS registered at a server, then all other drives with a total space that is less than 1 TB will be disabled for recording at the server. This is done to ensure a correct write-ratio calculation and to improve overall system stability.
- External storage drives can also be assigned through the DW Spectrum Client. Storage options include local storage to the available HDDs on the server computer, Direct-Attached Storage (DAS), and Network-Attached Storage (NAS).
General DW Spectrum Write-to-Archive Process
- IP camera video streams are detected and captured by the DW Spectrum Media Server and stored in RAM.
- The DW Spectrum Server writes captured IP video in RAM to available storage (internal hard drives or NAS) once per minute.
- All suitable drives are written concurrently and according to a ration that the system calculates for their sizes. For example, if a single server has multiple hard drives of varying sizes, DW Spectrum will fill up each hard drive at the the same rate to ensure that no individual drive’s system bus is overloaded.
- DW Spectrum keeps some space reserved on every drive so that performance is not affected while archiving.
- When any storage drive is full, DW Spectrum will begin to overwrite recorded video starting with the earliest/oldest video on the server across all the drives until there is enough space to record a given amount of data. This is done while DW Spectrum actively archives video to its media storage. As a result, a solid Timeline can be maintained.
- DW Spectrum prevents recording onto the system drive if there is any storage drive installed on the server that meets the minimum requirements and is at least 5-times larger than the system disk.
- The User cannot manually modify the archive (delete/add/etc.) through the DW Spectrum Software.
How Hard Disk Failure Is Managed
If a single drive in a multiple drive system fails, the DW Spectrum system will do the following:
- Continue writing to all of the remaining available drives.
- Create a notification in the DW Spectrum Client’s Notifications panel to inform Administrators that a drive failure has occurred.
- Rebuild the archive index after the Media Server has restarted.
- If the Failover-on-Hard-Drive-Failure is enabled, then the cameras that were writing to the failed drive will begin to record to the next designated failover server.
What Happens After Adding Storage
When users add storage to an existing system, newly recorded data will be divided equally between all storage drives. Old/existing storage will accommodate the change and will fill at a slower rate than before, slowly increasing the archive retention period overall until all drives (old and new) have filled up with an equal percentage of data.
The server will provide an estimate for all storage space and the predicted archive retention time once all drives hold an equal percentage of data. Typically, after X months from the date that new storage drives are added, all storage drives should hold an archive for X months if the predicted archive retention time is also X.
For More Information or Technical Support
DW Technical Support: 866.446.3595 (option 4)
https://www.digital-watchdog.com/contact-tech-support/
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DW Sales: 866.446.3595 [email protected] www.digital-watchdog.com
