- Users can reserve channels in advance, so that no additional cost is required
- Servers are better at handling larger expansions.
- Proper planning by consultants or integrators is a key requirement for a cost-effective solution meeting the required security levels
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A very important consideration when setting up a video surveillance system is foreseeable expansion. The number of channels that an end user foresees expanding will have implications during the original installation. Small expansions are easily accommodated. Since NVRs come with specific channel numbers, extra channels can be saved for future expansion. “For future expansion, users can reserve channels in advance, so that no additional cost is required,” said Ricky Law, Sales Engineer at Ensec Solutions. However, adding extra appliances will require system downtime and rewiring.
Servers are better at handling larger expansions. Extra cost is needed in additional licenses for additional channels, but extra servers may not be needed as extra hard-disk drives (HDDs) can be directly added to existing servers.
Failsafe Measures
For added assurance, common points of failure should also be considered. By thinking ahead, the amounts of downtime and lost data can be minimized. As HDD failures occur frequently, many vendors offer servers and appliances with RAID options for video surveillance: 0, 1, 5 and 6. Hardware RAID is more expensive and is better at preserving data. Software RAID is less expensive but requires more processing power. If your data is mission-critical, hardware RAID may be a safer bet. “When NVR activity exceeds NVR capacity, when NVRs fail, and when NVRs are upgraded, these all require manual intervention in the field and can lead to system downtime,” said Lee Caswell, founder and Chief Strategy Officer, Pivot3.
Design features could help minimize the damage or downtime from an NVR or server. The number of channels per server or NVR could be limited to reduce the number of black cameras in the case of a server or NVR failure, Stephen Beckmann, Video Product Marketing Manager in EMEA, American Dynamics, (a Tyco Security Products company).” suggested. Backup storage, perhaps in the form of another NVR, could be configured in hot failover mode, to take over when the first NVR fails. Due to the flexibility of NVRs, an integrator can simply bring a dysfunctional NVR back to the laboratory to do repair work and minimize cost, whereas the service required with PC servers is much more intensive and requires longer hours out in the field, Law said.
Bigger Picture
A recording and storage solution that accounts for all of these factors — system architecture, storage distribution, system management, computing power, stability issues, foresight — will be better able to cope with the end user's current and future needs, and be more cost-effective in the long run. “Proper planning by consultants or integrators is a key requirement for a cost-effective solution meeting the required security levels,” said Beckmann.
It can get very complicated with large jobs, Larson cautioned. A recently completed video installation with 1,900 megapixel cameras fed video information into 40 servers, and then passed the information into a SAN for centralized, long-term storage. “In this scenario, you can't just take in all the cameras to the 40 servers, and then have all the 40 servers send all those cameras to the central storage,” said Tom Larson, Director of Global Accounts, BCDVideo. The case was handled by holding storage in the servers for a day or two, before dumping the data from the servers into the storage array on a schedule. This meant that a lower-performance SAN and a lower-bandwidth network could be used, reducing the overall cost. “If you had 30 to 40 servers do live storage, it could get very, very expensive.”
As the vast majority of monitoring was going to be done in store, with occasional bandwidth passing outside of gas stations, only a series of NVRs were used to achieve what was needed. A suitable video installation can come with a reasonable price tag.
“You have to start planning and engineering the total solution early on,” Larson said.