High disk activity...

[nettech_gt]

When I'm recording 3 three shows at the same time (3 HDPVRs) the disk activity spikes. And when I try to watch an already recorded show it plays in super slow motion. I have 2 GB of RAM free and my CPU load is between 1-6%. My recording drive is a RAID 5 (hardware) with 4 2TB WD red drives. Anything I can do watch a recorded show (not in slow motion) while three are recording?

[drewg]

Originally Posted by nettech_gt

When I'm recording 3 three shows at the same time (3 HDPVRs) the disk activity spikes. And when I try to watch an already recorded show it plays in super slow motion. I have 2 GB of RAM free and my CPU load is between 1-6%. My recording drive is a RAID 5 (hardware) with 4 2TB WD red drives. Anything I can do watch a recorded show (not in slow motion) while three are recording?

That load should be trivial (5-10MB/sec write, and 1-2MB read, or 7-12 MBs if comskipping during recording), so it suggests that something is really wrong with your settings. But you don't mention what OS or RAID controller you're using, so all you're going to get is very general advise.

If this is a new array that you don't mind destroying & re-creating, you might want to try changing the stripe size, and making sure the filesystem block size is large enough, etc.

If this is an existing array you'd rather not loose, you might want to play with the controller's read-ahead and write-caching policies. I'd see if using write-back caching, and setting the read policy to read ahead (or adaptive) helps.

If you're running comskip, you might want to turn it off temporarily to see if that's whats pushing things over the edge.

In general, software raid in *nix works far better than hardware raid. Not sure about windows. With my setup (ZFS RAID-Z, which is like Raid5, but better) I have no problem recording 4 shows at once, all getting comskipped, while 2 HDx00 extenders are watching something, and Plex is transcoding something else for my kid's tablet, and I've got a few VMs running doing other things (compiling code for work).

Drew

[MattHelm]

I've done what you are trying to do on a single WD Green drive, so I'd say something is wrong with the array, as drewg said.

Please list your hardware.

[sflamm]

My recording drive is a RAID 5 (hardware) with 4 2TB WD red drives

Is this a RAID card inserted in the server? If so something is seriously wrong, as that is nominal load on a hardware 4x RAID array. The Red drives are quite fast sequentially reading/writing which is what is happening for video recording - and even faster since the RAID 5 is striping inherently.

If this is an external RAID box you bought (my guess) then it is a POC.

[sflamm]

Another possibility is that you have commercial detector running (as I do) and what is happening is the server is completely bogging down on CPU cycles... (POC server cpu ). If that is the case then change your commercial detector to only start detecting when the recording is finished and not realtime.

[nettech_gt]

Thanx to everyone who replied. I have a 3ware 9500S-4LP RAID card. I turned on write cache as drewg suggested and it seems to have fixed the issue.