RAID1 – What Say You?

IPVideo Corporation has been manufacturing RAID1 storage options for its video management systems for the past year Our customers, particularly those that do not have the resources to effectively monitor total system performance, have found RAID1 to be a reliable and user friendly approach for critical storage.

Some of the reasons IPVideo Corporation recommends RAID1:

All data is mirrored on both hard drives in the array for redundant protection of all recorded video. This is normal data, no striping.

RAID1 provides a simple rebuild process; upon hard drive failure, plug in a new drive and walk away. No user intervention required.

RAID1 allows the user to remove a hard drive at any time without causing any downtime. Users can provide authorities with the actual hard drive the video was recorded on, retaining the chain of evidence. Video can be played back on any PC with USB attached drive carriage.

RAID1 will auto-rebuild. Video will continue to store normally during array rebuild process. No particular vulnerability. RAID5 takes a significant amount of time to rebuild in the event of a failed array. RAID5 is in a degraded state during a rebuild and is vulnerable to data loss in the event of a second drive failure. The data is also vulnerable to loss until all the data that was on the failed drive is rebuilt onto a replacement drive.

RAID1 stores fewer video streams per drive letter, this improves load balancing as compared to other RAID levels that consolidate drives on to one stripe or drive letter since Windows effectively uses the extra throughput of the extra physical spindles.

RAID1 has a lower failure rate. For example, consider a RAID 1 array with two identical models of a disk drive with a 5% probability that the disk would fail within three years. Provided that the failures are statistically independent, then the probability of both drives failing (with no replacements for 3 years) is 0.25%.

RAID5 configurations suffer from poor performance when faced with a workload which includes many writes which are smaller than the capacity of a single stripe.

If you have a comment or some insight into RAID options for security video storage we would appreciate hearing from you.

Wireless – Less is More

The installation and use of commercial quality long range point-to-point wireless network links provides great flexibility in IP camera deployment but is generally associated high cost and somewhat challenging technical problems.

We have recently engineered several wireless IP camera installations using the EnGenius 3220 series of high powered outdoor wireless AP/Client Bridge equipment. While there are many better-known makes, we find the 3320 series offers these advantages:

-Models with 5dBi omni, 9 dBi patch, and 16 dBi patch antennas built-in.
-Low cost, around $150 per unit which is the low end of the general price range.
-Simple installation and set-up, point-to-point or point-to-multipoint.
-True 802.af Power over Ethernet (PoE) operation (many use a non-standard PoE).

The available antenna configurations are very flexible, good mouniting brackets are included, and PoE injectors and power supplies are included, making for easy installation. The built-in antennas eliminate the need for RF cables and potentially leaky connectors.

A lesson we learned the hard way is that when the path is relatively short (100 to 500 feet), the units should NOT be run at full power. The high output of the radios causes overload which actually prevents proper operation.

Trees in the LOS (line of sight) path do reduce range. The units have a web page based signal strength indication which helps with antenna alignment but lack any external readout. The 16 dBi unit has a half-power beamwidth of 30 degrees while the 9 dBi offers 60 degrees.

This equipment is available from specialty reseller DoubleRadius and other more general distributors.

Help From Afar

The ability to administer a network video system from a remote location is a great time and cost saver. Windows remote desktop is commonly used for this purpose but does not work well with IP video environments. There are several available solutions that do work and an open source remote control package we highly recommend is UltraVNC.

UltraVNC consists of a server part installed on the machine(s) you wish to control remotely and a client part installed on your local machine. The machine(s) running UltraVNC server must be reachable by an IP address or Domain. Note that this IP address or domain could be temporary as long as it does not change during the remote control session. Complete installation instructions are provided for UltraVNC.

By default UltraVNC requires ports 5800 and 5900 to be open in your firewall. These ports may be changed if need be. You should not expect video viewed through UltraVNC to be of good quality – this package is meant for control and admnistration and will serve the purpose very well.

The Vivotek FD7131 IP Dome Camera

An affordable and effective IP dome camera has been a holy grail in the network video world for some time. We have tested the Vivotek FD7131 in depth, and while it’s not perfect, the camera offers many unusual features together with very good preformance for the price. The image quality is quite good at 640 x 480 and the 2-4 MM vari-focal lens provides a FOV of over 90 degrees with minimum fish-eye distortion. The list of less common features includes PoE or 12V power, internal or external microphone, line-level audio output jack, PIR motion detection, and useful visible local scene lighting. Installation and mechanical adjustment are quite convenient and the user interface allows flexible setup of behavioural rules such as turn on the light for 20 seconds if a person approaches.

The camera’s dual codec streams Motion-JPG and MPEG4, and the audio quality (MPEG4 only) is quite good. All functions are accessible from the browser interface and it is easy to save standard MPEG4 movies with sound directly to disk.

The Vivotek FD7132 is similar but provides IR illumination as opposed to visible light and offers a more conventional 3.3 to 12 MM vari-focal lens.

Cameras with heavier construction and higher frame rates are available but at twice the price.

These cameras are supported by IPVideo Corp’s DynaView network video management system, and, if 10 FPS at full resolution will meet your needs, are a great choice well below $300.

XP PRO is King!

For those of us concerned about the migration of IP Video applications to Windows Vista this appears to be good news.

Axis Camera SNMP

SNMP (simple network management protocol) is a commonly used mechanism for monitoring and administration of network connected devices. These are also called SNMP traps. Axis has provided the following comment on the implementation of SNMP in their cameras and servers:

“Currently there are no SNMP traps included in our products; from what I’ve heard. It is planned in firmware 4.49 but is very limited. Just Ip change and link up.”

We will keep an eye out for SNMP implementation in other IP cameras and servers. There are several other ways to manage Axis IP cameras and servers.

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