Um, about those NVRs...

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Monday, October 1, 2007

The DVR is generally accepted as a pretty decent way to store video in digital format, whether directly from IP cameras or from analog cameras that are encoded into a digital signal. It's easy to install, end users understand fairly easily how to use it, and it offers the ability to view video over the Internet and add video analytic features. Plus, they're getting pretty big; many companies now offer two terabyte models, which easily store two months or more of compressed video. Not bad.
But what happens when the DVR goes bad? Most industry warranties end at three years, some go to five years, but none of those warranties can get your video back if the DVR's drive fails. How happy is your customer going to be when you tell him or her you'll replace the DVR for free, but that vital footage of an employee dipping into the till is gone forever?
"The problem is that the larger the hard drive, statistically, the larger the chance of error," said Bob Banerjee, product marketing manager for IP video products at Bosch Security Systems. "There's no magic behind it. And when the disc becomes corrupt, you run the risk of the whole DVR becoming unusable."
That has led a number of manufacturers and integrators to explore the option of the NVR (you may know all this, but bear with me), whereby the video management software is hosted on a PC on the network and the video is stored on a disc array, often via SCSI cable, and likely employing one of the RAID standards of distributed storage, all of which offer varying levels of disc redundancy. RAID5, for example, provides 16 disc drives, one of which can be removed at any time without any information being lost. So one drive dies, you pull it out, and then you plug in a new one, and there's no problem. Information would only be lost should two drives fail within, say, a couple hours of each other, as it takes a little while for a new drive to become integrated into the system.
"If you do lose a drive it's just a matter of getting the replacement in there before a second drive goes bad," said Dan Brault, president of San Diego-based integrator Electro Specialty Systems. "If you do RAID5 plus a spare, it's great because you have a hot spare, but then you're wasting a drive. For the video application, most people are happy with just a spare drive. They're not so concerned with a hot spare, it's just the redundancy they want."
So, great, you've eliminated the problem of losing information (other RAID standards offer even more redundancy), but now you have the new headache of the PC and its operating system in the middle, serving as the NVR. Know any IT departments that enjoy maintaining PCs and servers? Or you can attach RAID storage to back up a DVR, but then you need a whole disc array for each DVR, which can get expensive.
What if you could eliminate the middle appliance, and just move video data straight from the camera to the RAID storage? Well, you can, actually, through a standard called iSCSI (pronounced "eye-skuzzy"), which has been in use in the storage industry since the standard was ratified in 2003. Previously you had to use a standard SCSI cord, no more than three feet long or so, to attach a PC to storage (that's why you need a RAID for every DVR). According to the Storage Networking Industry Association, however, iSCSI "maps the SCSI remote procedure invocation model on top of the Internet's Transport Control Protocol (TCP) to produce a transport mechanism for storage over Ethernet. In other words, iSCSI encapsulates SCSI commands into TCP packets, thus enabling the transport of I/O block data over IP networks ... It also enables remote mirroring, remote backup, and true disaster recovery."
What's that mean?
"It enables the market to do a lot more in a lot cleaner way," said John Matze, vice president of business development at chipmaker Hifn and a co-author of the iSCSI standard. "I'm sure you have to pay a little more for the cameras and the storage, but your management of the PCs and DVRs is knocked down to just nothing, so what's that worth to you?"
Ready to supply you with the cameras is Bosch, which released iSCSI-ready cameras earlier this year. "We recognized that the NVR PC is a point of failure," said Banerjee. "NVRs are horrible things for the IT department to have to manage. So Bosch took out the smarts from the inside of the NVR and stuck it inside the camera. Now the camera provides the right kind of video and goes straight to the disc array ... This is a wonderful thing. We've all but stopped selling NVR software. When you can turn to people and say, 'You can go straight to the storage with nothing in between but a Cisco switch,' the IT department really thinks that's game over for the NVR."
Of course that's what Bosch would say, though, right? They're selling these things. But the storage guys like it, too.
Jeff Bell, vice president of marketing at security-centric storage maker Pivot3, said, "iSCSI for surveillance storage not only makes sense, it's the only choice that does." He said the benefits include higher scalability of storage capacity and bandwidth, more configuration flexibility through decoupling video servers and embedded storage, increasing the availability of video storage, and reduction of installation cost. "As a storage protocol, if thoughtfully implemented, iSCSI can be an ideal exploitation of IT infrastructure," Bell said.
Brault, at Electro Specialty Systems, has already done a number of installations with the Bosch cameras and iSCSI storage. "The main thing we see," he said, "is that it's a much more cost-effective way to put in an IP system if you have a number of existing analog cameras and you've got a series of DVRs. When you go to upgrade that, you're dealing more and more with customers' IT departments, and they're looking for a RAID storage solution. They don't like the failure of DVRs. They want something better than that. The iSCSI is the most cost-effective way of getting a RAID5 to a customer." He said iSCSI is also very helpful for remote locations, where it's inconvenient or impossible to store a PC or DVR.
"I don't know why other manufacturers aren't [working with iSCSI], I really don't," said Brault. "At the last ISC show, still nobody had it and nobody was really talking about it. I don't know why other manufacturers haven't jumped on the bandwagon."