Should RAID be used in CCTV and what are the pros/cons? What are the alternatives?
RAID5 systems are typically used in CCTV when storage capacities are high, or where they are specified in a tender. However, they are not ideal for video and alternatives exist.
First and foremost we must understand that there is a world of difference between IT data and video data. At the fundamental level, both consist of a series of ones and zeros, but the difference lies in how the data are generated, stored, modified, retrieved, presented, exported and deleted. These differences are amplified in large-scale systems and significantly affect the total cost of ownership.
As hard disk capacities grow larger, RAID5 rebuild times grow longer, exposing the storage array to an increased likelihood of total data loss, especially when it must continue recording during the rebuild process. RAID6 provides another level of protection, but with lower speed, higher cost and even longer rebuild times. These drawbacks are not a problem for IT-based storage, where multiple backups exist and RAID systems can be rebuilt offline. This is not normally an option for video surveillance systems.
Sequential storage systems, designed specifically for video surveillance, are a better and proven alternative for video data. They are particularly beneficial for high-capacity applications and/or long file retention times. By removing or mitigating against the factors which cause disks to fail (temperature, vibration and wear) they obtain far higher reliability even from very low cost hard disks. A mirrored-overlapping pair writing pattern provides protection against disk loss without requiring a rebuild process. The systems are simple, very low power and very easy to maintain. Unlike RAID, disks are removable for evidential purposes and are directly playable. Very low total cost of ownership is achieved significant savings on disk replacement, power costs, cooling costs, cooling equipment and far smaller UPS requirements.
Key Account Sales Leader UK & Ireland ADI Global Distribution at ADI Global Distribution
8 年A good article! The cost of IP cameras and recording is now much lower and delivers more technology for the investment, allowing consideration for suggestions such as failover and mirrored recording.
Head Enterprise at IDIS India #IP CCTV #NVR | Retail Solution | Hotel & Hospital Solutions| Insitutional Solutions| Ex-Schneider Electric | Ex-Siemens
8 年Agreed and it is an commercial value add being given by major IT OEM's , the fact is far from the increasig cost of entire IT infrastruture of a True Electronic IP CCTV System and same time discounting the fact of actual comparion as well
The Health Guardian
8 年are there many makers of direct storage devices
International sales and business development with technical knowledge and world wide experience
8 年Agree, and that's why in Our DigiEye DVRs and NVRs as in Hybrid line we have as option internal RAID-1 (mirroring) and as advanced option also redundant internal power supply. https://www.techboard.it/downloads/syactb_datasheets_digieye_dvr_hvr_nvr_it_web_3g.pdf
Operations Manager at Veracity Ltd.
8 年A hugely environmentally beneficial solution.....