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Hi,
We've been noticing something on our render farm for some time and I decided to a take a look at it as we are experiencing saving our renders to disk after completion has been taking longer then expected.
Initially we thought it was a network I/O issue, but after some testing and saving the render to the local drive on each render node first we could see in the VRay Standalone logs that it was something else.
It turns out that the DWAA/DWAB lossy compression for EXRs is very slow compared to ZIP compression. In one test render in 5k resolution(with a couple of Render Elements) it took 1 minute and 47s to write the EXR when using DWAA compression, but it took 3s when using ZIPs compression.
That might not be very much time when doing a single high res still, but when rendering a animation and a lot of sequences that time starts to build up... In some cases the save/write time with DWAA has been almost 4 minutes for one frame.
Can you have a check on this and see if there has been any updates to the OpenEXR libraries or similar that might result in better save performance, or if there is anything else that can be done.
We've been noticing something on our render farm for some time and I decided to a take a look at it as we are experiencing saving our renders to disk after completion has been taking longer then expected.
Initially we thought it was a network I/O issue, but after some testing and saving the render to the local drive on each render node first we could see in the VRay Standalone logs that it was something else.
It turns out that the DWAA/DWAB lossy compression for EXRs is very slow compared to ZIP compression. In one test render in 5k resolution(with a couple of Render Elements) it took 1 minute and 47s to write the EXR when using DWAA compression, but it took 3s when using ZIPs compression.
That might not be very much time when doing a single high res still, but when rendering a animation and a lot of sequences that time starts to build up... In some cases the save/write time with DWAA has been almost 4 minutes for one frame.
Can you have a check on this and see if there has been any updates to the OpenEXR libraries or similar that might result in better save performance, or if there is anything else that can be done.
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