Would it possible to add a pause and resume button for the tasks: This way we don’t lose the progress of the rendering.
Or rendering in the task the missing frames only: For example if we sent a job with 3 frames per task and it got to 80% and we had to stop it would have the possibility to render only the last frame of the task and not the hole task again.
Sometime we have to stop the task from rendering because we need it to render another job or because we need to use the PC.
We lose all the task and we have to render it again fro scratch losing sometime 5 to 6 hours of render.

Are you doing multiple frames per task? Set your task size to 1 frame.

Chunking tasks is really only useful if your frames are very quick. This helps to alleviate overhead between tasks from slowing down the overall render time. If your frames are taking hours to render, you should definitely leave the frames per task at 1.

Well the thing is that it takes time for the scene to load and start rendering in deadline, sometimes from 5 min to 10 min, so imagine if we had to sent frame by frame for an animation of 600 frames, you would lose 3000 min to 6000 min of render time, this is why we usually prefer to send from 2 to 3 frames per task.
Now there is another issue, sometimes we don’t really know how much time the frame is gonna take to render until we send it to deadline(cause we send it high quality with high settings), this is why we prefer to send it per group of 3, avoiding to lose time on reloading the scene.
Plus you have to take in consideration that its not always a big company that uses deadline, we don’t necessarily have a render farm of 100 of nodes that let us afford to waste a little bit of time, in our case we render on 6 PCs only.
And to add to the original post, sometimes we have to switch to another job urgently, and sadly we have to lose the previous job progress(and it could be some hours of render).

What 3D application (Maya?) and what renderer are you using?
Deadline is supposed to keep the scene in memory between frames for most major 3D applications, unless requested otherwise. Are your slaves actually reloading the scene after each frame?

If this is Maya, you’ll want to enable the “Use MayaBatch” option in the submitter to keep the scene loaded in memory between frames.

In Deadline, chunked tasks are considered a single entity, which is why the whole thing needs to be re-rendered. By keeping the scene loaded in memory, that should offset the majority of the wasted time so you can keep your task sizes at 1 frame.

Ok good to know, and yes its maya.