My name is Danny Laubly and I am a Systems Integration Engineer with Pelco. This thread was brought to my attention and I wanted to help clarify a few things, although ChrisL has done a good job of that already.
In reference to the presentation that mirodrig linked to, that page is being taken out of context. It was also generated 3 years ago. The way it functioned is this:
If you have a group of cameras you want to record onto 2 NSM's (Storage boxes), you would create a storage pool. That group of cameras would be split up between the two NSM's, and every 30 minutes, the cameras would rotate between the two NSM's. This way, in the event that something brings one of the NSM's offline, you are not missing all of the video for half of your cameras, but some of the video for all of your cameras. Once the offline NSM comes back up, all of the video would then be available again.
The screenshot on page 25 of the presentation is showing the difference of losing an older NVR that would have a set group of 48 cameras on it, and a 10 NSM storage pool with up to 500 cameras where 1 unit went offline. It's hard to tell in the screenshot if you don't have the context, but the timeline is zoomed pretty far out, and the gaps are exactly 30 minutes in length. This demonstrates that if you have 10 NSM's in a pool, and one goes offline, you'll have a 30 minute gap on all of your cameras occur every 5 hours, which we feel was better than losing 100% of all of the video for the cameras being recorded on a NVR.
Again I want to re-emphasize that the gaps shown in the presentation are expected if one of your storage boxes is offline. Under normal operation you should not see gaps.
For anybody in this thread who has questions about how Endura works, or if you are having problems with your system, I would love to speak with you directly. Feel free to contact me any time. My contact information is below.
Thanks for your time,
Danny Laubly
Pelco - Systems Integration Engineer
danny.laubly@schneider-electric.com
1-800-289-9100 x4416