Inconsistent rendertimes

[Neilg]

I'm not sure if this is just a vray problem because it is happening on the same farm machines each time... but the only problem is that those machines make up just over 1/3 of the farm.

I've noticed it before but never this bad. The last job I did had a couple of frames here and there that took twice as long but this is pretty bad.


Rendertimes are around 10 minutes on some machines and up to an hour on others.
The scene is about 1.5mil polys, couple of displacement objects, couple proxy trees but nothing too heavy. Certanly nowhere near as heavy as some i've done before.

The farm machines are all exactly the same and were bought at the same time, boxx ones. 4gb ram.

The weirdest thing about this is what happens to the progress bar in vray - when the render is pretty much finished the progress bar seems to think it's only done 1/4 or less, then it ends with the progress bar still way over on the left. Actual renders look exactly the same.

The scene loading isnt affected at all - they start rendering in the same time, it's just the actual rendering part which is slow.



Anyone seen anything like before/have an idea what could be causing it?

[jacksc02]

are the pagefiles set to the same thing on every machine?

[Neilg]

You're a lifesaver.

Some of them had auto switched to 6gb. The problem machines were set to 2gb.
I guess the slowdown was vray having to do some crazy swapping things in/out of memory then.

[jacksc02]

Been doing this a while now
You can buy me a pint or 10 next time your in london

[Neilg]

I probably do owe you a few by now, haha.


I just did a test on that though and it's not made a difference to the rendertimes, i'm restarting them now but your pint may be in danger...

[jacksc02]

It could also be a bottleneck on your server with the proxies with all machines trying to grab the same proxy file at once.
What is your network like?

[Neilg]

I did think that originally but it's the same machines each time - also happens on a totally empty farm with no network traffic.

[jacksc02]

Whats the ram useage like between the quicker and slower machines when its rendering?

[QuakeMarine1]

i have notice issues like that if the scene contains DOF or motion blur

[vlado]

I'm not sure if this is just a vray problem because it is happening on the same farm machines each time... but the only problem is that those machines make up just over 1/3 of the farm.

I've noticed it before but never this bad. The last job I did had a couple of frames here and there that took twice as long but this is pretty bad.

Rendertimes are around 10 minutes on some machines and up to an hour on others.
The scene is about 1.5mil polys, couple of displacement objects, couple proxy trees but nothing too heavy. Certanly nowhere near as heavy as some i've done before.

The farm machines are all exactly the same and were bought at the same time, boxx ones. 4gb ram.

The weirdest thing about this is what happens to the progress bar in vray - when the render is pretty much finished the progress bar seems to think it's only done 1/4 or less, then it ends with the progress bar still way over on the left. Actual renders look exactly the same.

The scene loading isnt affected at all - they start rendering in the same time, it's just the actual rendering part which is slow.

Anyone seen anything like before/have an idea what could be causing it?

Is this repeatable for the said frames? If you re-render them (on the same or other machine), do they still take longer? Also, which 3ds Max version?

Best regards,
Vlado

[Neilg]

Chris, ram usage I think is the same.
Quake marine - theres no DOF or motion blur...

Vlado - if I re-render the frame on the same machine it'll still take ages, but it's fine on other machines.
We're using max 2010, most recent vray. I think the only plugin in the scene is colourcorrect.

Do you know why the progress bar gets messed up? When the buckets are pretty much done with the rendering the progress shows about 1/4 or less done, then just finishes anyway.

[jacksc02]

Im taking a very wild punt here, but have you de-fragged any of the render machines lately?

[Neilg]

Heres the progress bar issue:
This exact frame/IR map was rendered on another machine - the third pass took 7minutes and it rendered fine.
This is being done with the triangulation mode so it's just over half way through there, yet the progress bar thinks it's done 1/8th of the image.
3 of those boxes were done with the first couple of buckets - it slows down as the render goes on.



This is worse than the slowdown if anything because it makes absolutley no sense whatsoever.


edit: I'm not sure chris, i dont think we've done them in a while. The only thing installed on them in max/vray, theres 50+gb free space on a 60gb drive.
I'll test that on one of them though, shouldnt take too long.

[tricky]

Network bottleneck? How many machines do you have, all chucking bitmaps, saved solutions, proxies all over the place? Is your switch managed and up to it?
(just an idea)

[add101]

just a shot in the dark, but do you have any antivirus on render slaves? i generally keep network pc's off the internet, so don't update often. maybe a virus has got onto those pc's on a flash or something.