From The Edge To The Cloud
Storage is an important consideration for any video system
- By Robert Kramer
- Jul 01, 2012
System designers must ensure
that sufficient storage is available
to archive video for the
required length of time and
at the required frame rate and
resolution. Changing technologies in today’s
market are altering storage needs, making it
essential for designers and integrators to maintain their expertise so that they can
best advise their customers on the right storage solution to meet their needs.
Traditional storage options include DVRs, a standard piece of an analog system
and NVRs, typical for IP systems. Both DVRs and NVRs have internal harddisk
drives (HDDs) that provide storage, and expansion devices can be used if
more storage is needed. Today, storage solutions are migrating rapidly to incorporate
cloud-based solutions, as well.
Enhancing Access to Stored Video
Today’s more intelligent solutions enable recorders to provide additional value
with greater functionality related to retrieving video. User interfaces have evolved
and now offer capabilities such as intuitive search features to review video based
on a calendar and timeline and flexible playback controls that allow users to jump
to a specific time/date or to a variable number of seconds before the end of a recording.
Filtered searches can target time and date, event type and camera number.
Some new NVRs feature even more advanced capabilities, including embedded
face-matching technology that compares face images obtained from a connected
network video camera (equipped with face-detection capability) with
faces previously identified and stored in the video recorder. When a match is
found, an alarm notification can be sent by email, system alarm, terminal output,
buzzer or indicator. This capability, designed as a security solution for small
retail and other specific environments, demonstrates an added-value approach
to using stored video. Additional software capabilities also can be used to count
visitors, track visit times and even estimate the age and gender of people captured
on video. This new functionality could help a retailer track customer patterns,
and it can provide useful demographic information.
How Much Storage is Enough?
Advanced functionality is dependent on a recorder’s ability to store video. But
how much storage is enough? Too little storage undermines system performance,
and too much storage can be a waste of resources and increase system costs. Determining
the required storage involves a simple calculation based on the number
of cameras, the data requirements of their image size and frame rate, the effectiveness
of compression and the number of days of recordings to be saved to meet the
Real-time video at 30 fps, especially from a megapixel camera, for example,
requires a lot of storage to retain evidence for 30 days, which is a standard in many
applications. Less storage is needed if a slower frame rate is acceptable, if a lowerresolution
image is sufficient—especially in off-hours—or if retaining video for a
day or two is sufficient. Careful analysis by the integrator, combined with discussions
with end users about how they will use the system, is the best approach to
evaluating storage needs.
When additional storage is needed, the most basic option is to use directly attached
storage (DAS). This often takes the form of expansion storage provided by
the DVR/NVR supplier. Each DVR/NVR uses its own DAS to archive video from
its connected cameras. Additional storage can be added to an NVR by installing
additional HDDs and using expansion units.
It is interesting to note that server and storage solutions have made great strides
in energy efficiency over the last five years. At one time, HDDs were among the
largest energy-usage components in a large server or storage solution. Today,
HDDs’ power usage has dropped by half compared to five years ago with the
adoption of more efficient motors and better circuit-board technology. A host of
software technologies now monitor HDD efficiency, adjust settings and use smart
control so that HDDs spin up to full speed only when needed while other drives
remain idle or spin at a slower speed. As solid-state HDD capacity increases, it
can eventually replace the higher-power requirements of spinning motors used in
current HDD technology.
Network Storage Options
Today’s IP-networked video systems provide other options when it comes to storage,
including network-attached storage (NAS) and a storage area network (SAN).
A networked device that contains one or more HDDs, often arranged into a redundant array of independent disks
(RAID), NAS is a single storage appliance
that supports multiple servers in
a network. The NAS devices maintain
their own IP addresses and can be set
up to share files among various users
on the network.
Another storage choice is SAN,
which is suitable for large networks that
require a lot of centralized file storage
or very high-speed file transfer operations.
Rather than using multiple NAS
devices on a network to meet storage
needs, a system administrator may
choose to use a single SAN with a highperformance
disk array to provide the
needed scalability and performance.
Storage in the Cloud
and at the Edge
An emerging option for IP network
storage that has intriguing possibilities
for video applications is off-site
storage, also known as SaaS or cloud
storage. Video storage is provided as a
service over the Internet by companies
using massive data centers around the
world that provide unlimited capacity
and 24/7 access. This approach is an
emerging trend in the video surveillance
arena because of lower costs and
Cloud-based video storage is priced
at a fraction of what network storage
devices cost when measured per gigabyte.
The cost-savings alone suggest a
growing role in the future for this type
of storage. The security of video images
stored off site is a top priority for cloudbased
system suppliers, offering another
potential advantage of this solution.
Access to cloud-based storage
across the network may be similar to
how an NVR accesses on-site network
storage. Another scenario involves accessing
off-site storage using a cloudbased
software application that takes
the place of an NVR. Off-site cloudbased
storage can be useful as a backup
in case local systems go down.
Storage also is available inside the
camera itself. Many cameras provide
SD/SDHC memory card slots that enable
use of computer chips to provide
manual recording, alarm recording or
backup JPEG recording if the network
fails. This capability at the edge of the
network provides backup recording in
case a system goes down, and it can be
a localized complement to cloud-based
storage. Edge-based storage can also
mitigate the bandwidth requirements
of a system.
Ensuring Seamless Operation
Market developments such as megapixel
cameras and new video compression
standards continue to impact the storage
needs of current and future video
surveillance systems. Understanding
the technologies and the needs of each
application directs the selection of storage
options. Integrators and end users
can continue to look to manufacturers
to be at the forefront, ensuring that
technologies work seamlessly with all
the various system
This article originally appeared in the Security Products Magazine - July 2012 issue of Security Today.