The challenges of storing video
Aug 1, 2008 12:00 PM, By Arun Taneja
An examination of video storage platforms
Reliability
Broadcasters require 100 percent up time, which demands protection from failure while allowing upgrades without disruption. In addition to hardware redundancy, RAID-type data protection is also a requirement. However, many video storage implementations are moving away from traditional RAID protection to other protection schemes that provide faster rebuild times in the event of a disk failure. Keep in mind that as capacities grow, the chance of a disk failure increases with the number of disks. This means the system must be able to rebuild quickly without impacting performance over long periods of time.
Video intelligence
Today's servers are highly intelligent devices with built-in diagnostics, volume management, snapshot, point-in-time copy and remote replication. In addition, some servers provide video-specific functions that optimize video storage and retrieval.
Other servers can automatically move frequently accessed data blocks and files to the outside of disks to improve disk seek times and performance. A server can even provide transcoding. This allows content to be converted to different output formats, helping create new revenue possibilities via new channels.
Direct attached storage
Some applications still store their data on inexpensive direct attached storage (DAS). This solution represents one of the most basic storage deployment options, where disk drives are either embedded in or directly attached to a single server. To access the content, workstations must be networked into the server. DAS storage still represents a large percentage of the video storage market, especially in price-sensitive applications like video editing.
This approach works well for applications requiring only small amounts of data. However, for most video tasks, DAS-based storage solutions can quickly become multiple islands of storage that are hard to scale and complex to manage. In addition, the initial cost savings of DAS can quickly be consumed by the operational costs or business impact that result from these limitations.
Traditional SAN and NAS
Traditional Fibre Channel SAN or NAS storage devices also can be used to store video data. If a company has a relatively small amount of content and a large investment in existing SAN or NAS technology, then these storage devices may provide a cost-effective approach for storage without having to retrain operational staff.
However, if the objective is to store large amounts of media-rich content with high-throughput requirements, then traditional SAN and NAS storage devices will not be cost-competitive compared to newer clustered storage architectures. In addition, traditional separated storage devices will likely run into performance, scalability and manageability limitations that will further exacerbate costs.
Clustered IP storage
IP-based clustered storage represents a cost-effective alternative that meets the unique requirements of video. Based on commodity servers and disk drives, clustered storage systems have many of the cost advantages of DAS. However, clustered storage can aggregate multiple storage nodes into a single logical system. Using this modular approach, performance, capacity and bandwidth can be scaled incrementally as needed while preserving the simplicity and manageability of administering a single virtual storage device.
IP-connected storage provides the bandwidth and performance required by media-rich applications without the additional cost overhead and operational complexity of deploying Fibre Channel SANs. Storage applications may use iSCSI (block-level), NAS (file-level) and object-level interfaces for the storage and retrieval of video content. Each of these interfaces has its advantages and disadvantages, and depending on the application, one may be more appropriate than another.
Overall, clustered storage architectures are well-suited for the demanding requirements of video applications. However, even within this approach solution, there is no one-size-fits-all solution. Most clustered IP storage solutions can meet the needs of generic video applications. So, while many broadcast-specific company names may come to mind, there is actually a variety of less-well-known vendors providing excellent video storage solutions.
Storage as a service
One option for companies looking to store video or other multimedia data is the storage-as-a-service (SaaS) delivery model. Vendors that deliver SaaS provide a simple Web-service-based API to store and retrieve multimedia objects in their hosted storage. Costs to store data fall between $1500 to $2500 per terabyte per year, with additional costs each time data is transferred in or out. While these rates may initially sound expensive, after factoring in the fully loaded costs to house, cool and manage in-house storage, SaaS storage services may be a financially viable alternative, depending on the data access requirements.
In addition, this option may be a useful and cost-effective disaster recovery/backup solution. Here the station faces only the storage and access costs, while not having to maintain a separate site, equipment and maintenance. This solution also solves the problem of keeping backup content well geographically separated from your on-air operations.
IP-based clustered storage is worthy of consideration as it provides an attractive solution to the handling of video and other media-rich content. Because of the sheer volume of video data being generated, traditional DAS, SAN and NAS solutions may no longer be the best economical choice. IP-based clustered storage is well poised to garner the lion's share of the video storage market.
Arun Taneja is the founder and consulting analyst with Taneja Group research and consulting firm.
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