Reusing Existing SAN for SurveillanceAuthor: Brian Rhodes, Published on Mar 18, 2012
Free Storage? Reusing an organization's existing Storage Area Network (SAN) for video surveillance can eliminate the need for buying a new storage system. However, many details impact this decision. In this note, we identify 8 vital attributes to consider when reusing an existing SAN.
Many corporations have existing SANs. These systems are often used to store emails, documents, accounting information and general company data. Just like SANs can connect to PCs, they can do so with many modern IP video surveillance systems.
Here are the 8 key factors that impact using the existing SAN for surveillance:
- Size of the existing SAN
- Expanding the SAN
- Connecting to the SAN
- Relationship with IT
- Cost Allocation
- Relative cost of existing SAN to new surveillance SAN
- Relative performance of existing SAN to new surveillance SAN
Size of the existing SAN
Determine if the SAN can handle the significant increase in surveillance storage. For example, if a SAN is sized for 16 - 20 TB, surveillance storage may consume twice that volume for even mid sized systems. While corporate SANs are sized with some additional overhead capacity for growth, the additional volumes that video storage consumes could grow beyond that capacity and disqualify the existing SAN from consideration. Othwise, considering the cost of expansion versus buying new purpose built storage quickly becomes the critical decision.
Expanding the SAN
Beyond just adding hard drives, factors like expanding the disk array chassis, OS liscensing, management utilities, and utilities consumption all contribute cost to expanding existing SANs. Many SANs are designed to be scalable, and bringing in the current provider during this discussion will help to identify the critical points in growing the existing SAN to support video storage.
Connecting to the SAN
Since the SAN may not be directly attached to the video surveillance system, video may travel across the LAN. Congestion should be considered. Some existing networks are not built at gigabit speeds, and the bandwidth consumed by video storage on a network may prove significant. This could result in lost video or choppy playback.
Relationship with IT
The relationship with IT is key to successful implementation. If IT is responsible for physical security, than this is simple. However, if IT and Physical Security are not under the same management, their relationship needs to be carefully examined. Many times, these groups do not get along. This is a major issue cited in not reusing existing networks and can have the same effect for SANs.
IT departments must understand that substantial resources will be required for storing video. Data or entire drives may be pulled for evidentiary purposes for extended periods of time. Video Surveillance sharing SAN space means that Security and IT need to jointly agree on issues of allocating cost of maintenance, service, and pulling of evidence.
Another issue to address is allocating the cost of storage and maintenance of equipment. Often, SANs are considered to be a general utility, but the space and uptime requirements of security may require additional and distinct cost. If greater uptime and performance is required of Security SAN space, then consider the accounting difficulty of attributing the additional costs. This problem is simplified when using purpose built surveillance SANs, because maintenance costs can be clearly attributed to specific hardware.
Performance of Existing to New Surveillance SAN
Existing implementations may not be configured to support heavy performance of video storage. A purpose built surveillance SAN may include performance monitoring and load balancing features not present with existing general SANs. Additionally, surveillance SANs often allow running VMS software on their appliances. This can eliminate the cost and need to have separate servers.
If the existing SAN is reused, determining who and how mainteance is performed is important. For instance, the SAN might go offline or the video surveillance system may not be able to access stored video on the SAN. When reusing, this can make troubleshooting and service more complex. Some users see this as a reason not to reuse as it can result in finger pointing and additional service complexity. As such, if the existing SAN is reused, clear policies should be put in place about how quickly and what people are allowed to service the storage system.
After all issues are considered and costs factored, reusing the existing SAN may not be the best option. Our poll results show that more than half of integrators have never done this. However, they also show that a distinct minority do this once in a while or sometimes. It certainly is not 'free' and organizational challenges can arise but it can be the right solution for some organizations.
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