I'll post my experience with Zoneminder....
In terms of it's web based UI....UGLY and not at all ordinary user friendly. Boss hates the interface and claims (on those grounds alone) that it doesn't work. If I had time to re-write my own UI I'd love it.
Moving on...
I was able to connect 10 IP cams (3 IP-native Axis M1113E, 7 analog converted via Axis camera server) to my rig which is running CentOS 6 64bit.
I had some challenges along the way but I will detail my resolutions.
My biggest issue was poor performance and dropped frames. My CPU wait states were typically above 1.5 or more, not good. (Granted I was running on PC hardware, not exactly "server class")
I resolved this matter with a number of things...
1. Installed the latest FFMPEG and FFMPEG-devel binaries from dag wieers via yum. Made sure my lib.so.conf had the right paths.
2. Made sure that user apache was a member of the video user group. You get nasty log problems (only shown while debugging) regarding FFMPEG use without that, or you have to adjust permissions on the video path itself.
3. Connected to all cameras and camera servers via RTP over TCP. Found that I had to add a ?tcp or &tcp to the end of each URL that I was using to connect with. FFMPEG prefers to use UDP and I found an active bug in either FFMPEG or Axis' firmware that breaks UDP connections. Switching to TCP clears that up while seeing somewhat of a minor performance lag due to having to deal with TCP re-transmits. Reliability did go up, so I guess that's a good compromise. In my case RTP/RTSP or RTP/RTSP/HTTP connection options didn't work. Only FFMPEG or simple HTTP. The H.264 stream that uses multicast was great for reducing bandwidth and providing a quality image.
4. Offloaded motion detection using the trick detailed on Zoneminder's site and the "nodect" option. Worked a treat, but the built in camera detection seems unreliable. Any one else have that issue? I get some events that don't tell the whole story.
5. Adjusted my shmall and shmmax shared memory settings based on calculations I had made from what I expected the streams to consume. (I run my cameras at their full native resolution, some are 800x600, others are 720x480.)
6. I made all adjustments to stream size and frame rate at the camera's end. Work's a lot better this way since there is no guesswork. The camera will limit the DVR accordingly. For those confident with their VAPIX URL writing skills I could see that it may be more convenient to make adjustments at the DVR's end. I found in my case that got me in trouble. I limit all cameras to 3 FPS.
As of now I enjoy a Linux based DVR on a software RAID-10 setup that has wait states of about 0.30 or so. While still not my ideal, much better then over 1.50. Most of my lag now is in the old P4 based hardware I'm running it on. I have a feeling that by migrating to a Core i7/Xeon system of some sort I'd be flying.
What I enjoy about it so far is that I just don't have the weekly crashes my old Netpromax DVR (ran on top of Windows XP using a CoMart capture card) used to give me. Zoneminder on Linux, while somewhat of a trial to setup, seems to run like a top when dialed in. I also like the fact that I have a web based interface. I can build my own montage page if I want to and present it to other users, or place on a wall mounted monitor. Never played with the smartphone app, but I may down the road.
Hopefully what I've detailed here helps... If you need more detail feel free to ask.
Has anyone used Axis' own solution for DVR software or BlueCherry? Love it, hate it?