Failed to create EXR file (2)

[Fredrik Averpil]

We just noticed an issue with V-Ray 3.5 stable build 27280 where some region renders wont be able to write the output EXR file. Is this something you are aware of?

EDIT: To be clear, most regions come out just fine. But we notice that some ~5% of the renders (totally unpredictable) errors out like this.

...
...

>>>b [2017/Apr/12|20:18:16] V-Ray: Rendering image...
>>>b [2017/Apr/12|20:18:16] V-Ray:  (Estimated time remaining:  0h  0m  0.3s): 10 % completed
>>>b [2017/Apr/12|20:18:16] V-Ray:  (Estimated time remaining:  0h  0m  0.3s): 20 % completed
>>>b [2017/Apr/12|20:18:16] V-Ray:  (Estimated time remaining:  0h  0m  0.2s): 30 % completed
>>>b [2017/Apr/12|20:18:16] V-Ray:  (Estimated time remaining:  0h  0m  0.2s): 40 % completed
>>>b [2017/Apr/12|20:18:17] V-Ray: Bitmap file "//FILESERVER_IP/prod/proj197/maya/sourceimages/wire_bump.png" loaded.
>>>b [2017/Apr/12|20:18:17] V-Ray:  (Estimated time remaining:  0h  0m  1.0s): 50 % completed
>>>b [2017/Apr/12|20:18:20] V-Ray: Bitmap file "//FILESERVER_IP/prod/proj197/maya/sourceimages/Thule.png" loaded.
>>>b [2017/Apr/12|20:18:28] V-Ray:  (Estimated time remaining:  0h  0m  7.4s): 60 % completed
>>>b [2017/Apr/12|20:20:14] V-Ray:  (Estimated time remaining:  0h  0m 50.4s): 70 % completed
>>>b [2017/Apr/12|20:21:26] V-Ray:  (Estimated time remaining:  0h  0m 47.3s): 80 % completed
>>>b [2017/Apr/12|20:21:27] V-Ray:  (Estimated time remaining:  0h  0m 21.2s): 90 % completed
>>>b [2017/Apr/12|20:22:52] V-Ray:  (Estimated time remaining:  0h  0m  0.0s): 100 % completed
>>>b [2017/Apr/12|20:22:52] V-Ray: Number of raycasts: 139976510 (548.93 per pixel)
>>>b [2017/Apr/12|20:22:52] V-Ray:   Camera rays: 2408639 (9.45 per pixel)
>>>b [2017/Apr/12|20:22:52] V-Ray:   Shadow rays: 95126728 (373.05 per pixel)
>>>b [2017/Apr/12|20:22:52] V-Ray:   GI rays: 51946085 (203.71 per pixel)
>>>b [2017/Apr/12|20:22:52] V-Ray:   Reflection rays: 15978414 (62.66 per pixel)
>>>b [2017/Apr/12|20:22:52] V-Ray:   Refraction rays: 20929498 (82.08 per pixel)
>>>b [2017/Apr/12|20:22:52] V-Ray:   Unshaded rays: 343720 (1.35 per pixel)
>>>b [2017/Apr/12|20:22:52] V-Ray: Light cache utilization: 7.16%
>>>b [2017/Apr/12|20:22:52] V-Ray: Premultiplied light cache utilization: 32.62%
>>>b [2017/Apr/12|20:22:52] V-Ray: Number of light evaluations: 196887145 (7.73 per pixel)
>>>b [2017/Apr/12|20:22:52] V-Ray: Number of intersectable primitives: 7736997
>>>b [2017/Apr/12|20:22:52] V-Ray:   SD triangles: 7736996
>>>b [2017/Apr/12|20:22:52] V-Ray:   MB triangles: 0
>>>b [2017/Apr/12|20:22:52] V-Ray:   Static primitives: 0
>>>b [2017/Apr/12|20:22:52] V-Ray:   Moving primitives: 0
>>>b [2017/Apr/12|20:22:52] V-Ray:   Infinite primitives: 1
>>>b [2017/Apr/12|20:22:52] V-Ray:   Static hair segments: 504
>>>b [2017/Apr/12|20:22:52] V-Ray:   Moving hair segments: 0
>>>b Failed to create EXR file (2)
>>>b Failed to create EXR file (2)
>>>b Failed to create EXR file (2)
>>>b Failed to create EXR file (2)
>>>b Failed to create EXR file (2)
>>>b Failed to create EXR file (2)
>>>b Failed to create 
>>>bEXR file (2) Failed to create EXR file (2)
>>>b [2017/Apr/12|20:22:52] V-Ray error: Cannot write output image file "//FILESERVER_IP/prod/proj197/maya/images/scene4/slices/scene4_slice31_VeloSpacePro3b_renderCam.0001.exr": "error writing file"
>>>b [2017/Apr/12|20:22:52] V-Ray: Total frame time  0h  5m  4.0s (304.0 s)
>>>b [2017/Apr/12|20:22:52] V-Ray: Cleaning up bitmap manager
>>>b [2017/Apr/12|20:22:52] V-Ray: Cleaning up texture cache
>>>b [2017/Apr/12|20:22:52] V-Ray: Total sequence time  0h  5m  4.0s (304.0 s)
>>>b [2017/Apr/12|20:22:52] V-Ray: Render complete
>>>b [2017/Apr/12|20:22:52] V-Ray: ========================
>>>b [2017/Apr/12|20:22:52] V-Ray: Clearing exporter memory...
>>>b [2017/Apr/12|20:22:52] V-Ray: Total time clearing exporter memory  0h  0m  0.0s (0.0 s)
>>>b Scene //FILESERVER_IP/prod/proj197/maya/scenes/scene4.mb completed.

Full log attached.
render_log.zip

[vlado]

The error code (2) means "The system cannot find the file specified." It might be a fluke in the Windows network code or maybe something else. I guess we can try to save the file a few times in a row if the first save fails.

Best regards,
Vlado

[vlado]

In the log file, can you tell me what is the original text for this line:

ERROR 17.04.12 20:22:52 J8759, T163: [2017/Apr/12|20:22:52] V-Ray error: Cannot write output image file "//FILESERVER_IP/prod/proj197/maya/images/scene4/slices/scene4_slice31_VeloSpacePro3b_renderCam.0001.exr": "error writing file" :bomb:

Specifically the :bomb: string should be actually a number if parentheses.

Best regards,
Vlado

[Morbid Angel]

The error code (2) means "The system cannot find the file specified." It might be a fluke in the Windows network code or maybe something else. I guess we can try to save the file a few times in a row if the first save fails.

Best regards,
Vlado

Vlado by the looks of the log they are on linux. I really don't know much about linux, the server that's being accessed is also linux based?

[vlado]

I'm not sure it's linux; the double slash to specify a file server is a Windows thing, on Linux you would normally mount the file system somewhere, I think. I could be wrong though...

Best regards,
Vlado

[bigbossfr]

I'm not sure it's linux; the double slash to specify a file server is a Windows thing, on Linux you would normally mount the file system somewhere, I think. I could be wrong though...

Best regards,
Vlado

When we render on cloud using linux render node, we mount everything with a double slash to be sync with windows. This is a little tricks.
But yeah, i don't know here what they use

[Fredrik Averpil]

In the log file, can you tell me what is the original text for this line:

ERROR 17.04.12 20:22:52 J8759, T163: [2017/Apr/12|20:22:52] V-Ray error: Cannot write output image file "//FILESERVER_IP/prod/proj197/maya/images/scene4/slices/scene4_slice31_VeloSpacePro3b_renderCam.0001.exr": "error writing file" :bomb:

Specifically the :bomb: string should be actually a number if parentheses.

Best regards,
Vlado

The original V-Ray output for that was:

[2017/Apr/12|20:22:52] V-Ray error: Cannot write output image file "//1.2.3.4/prod/proj197/maya/images/scene4/slices/scene4_slice31_VeloSpacePro3b_renderCam.0001.exr": "error writing file"

...where 1.2.3.4 is our file server's IP address.

A Python wrapper script initiates the render and filter each line outputted during render. In this case, it detected the string "error writing file" in that line and generated a message which was both printed to stdout and sent into a special errors channel in Slack so that the artist got notified about the problem. Never mind the ":bomb:" part, it's just an emoji added to the Slack message which doesn't translate into anything when printed to stdout.

To answer the Windows/Linux questions; the log is from Linux. Just like bigbossfr guessed/noticed, we are using UNC paths on Windows and mounting the file server's shares in a root folder (named "1.2.3.4") on the Linux machines which essentially makes the same path accessible cross-platform. Yup, it's a trick that helps a lot here and there.
Linux just throws away the extra slash and uses "/1.2.3.4" while Windows understands the double slash as a UNC path.

A bit of an update on the original issue:
During a re-render of the same job, we did not see this issue at all. I'm considering network issues on our end. However, if I could just request one future improvement; it would be useful to further get any additional information on the reason why the file could not be written. I can see the following reasons:

- Permission denied
- Path not found (not accessible)
- Some unknown error not being the two errors above

[vlado]

However, if I could just request one future improvement; it would be useful to further get any additional information on the reason why the file could not be written.

We don't get this information, unfortunately. All we get is the error code, which in this case means "No such file or directory".

Best regards,
Vlado

[Fredrik Averpil]

We don't get this information, unfortunately. All we get is the error code, which in this case means "No such file or directory".

Ok. Well, anyways. I doubt there's an issue with V-Ray here. I'll report back if this keeps happening.

[Morbid Angel]

Ok. Well, anyways. I doubt there's an issue with V-Ray here. I'll report back if this keeps happening.

One way to isolate vray from network issue would be to try to render a test using many textures etc with another renderer. When many machines pound the network it might get some glitch for sure...who knows could be the server too especially if they are mipmapped.