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Sentry mode USB drive too slow

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Sentry writes to the drive all the time it is enabled. That is why there is several minutes saved footage leading up to a sentry event. At present, there is no evidence that any footage is buffered to RAM, it is streamed to the drive on the fly, hence the 4MB/s required write speed.

Well, that's a crazy design! Surely a buffer wouldn't be difficult or expensive to include ....
 
Well, that's a crazy design! Surely a buffer wouldn't be difficult or expensive to include ....

-- Do the math .. 4 MB/second, several minutes of recording. The MCU isnt a huge PC with GB of RAM (its built to a price point), this kind of buffering is expensive (comparatively, I'm not going to argue about RAM costs here), and there are huge demands on memory for more critical things like driving, UI, AI etc etc.

-- Also, if the car were to buffer and then write, it would have to be in catch-up mode when an event triggered, and that might mean overlapping retroactive event flushing with real-time camera data.

-- Finally, these modes are designed for catastrophic event recording. The car might well be disabled within seconds of the event, and these are EXACTLY the kind of events you DO want recorded, so you record everything just in case, then delete uninteresting stuff later. Think flight data recorders in airplanes.

So no, it's not a crazy design. Far from it.
 
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Yes they do wear out but they also slow down when they get more full.

Try removing it and seeing how full it is (would be interesting if you could report back). I read 70% is about max capacity before slow down.

Once removed, and you checked/saved what you need, reformatting it may give you the speed back.

Thanks. I took it out and deleted everything on it. Not sure how full it was. I put it back and the error happened again. Didn't reformat though.
 
I also have a Samsung 256GB USB stick that started throwing “too slow” messages after a few months.

Someone mentioned surprise that people run Sentry Mode 24/7, but consider that lots of us live in condos or apartments with no private garage.

It seems the best solution (for constant recording) is actually to use a traditional 2.5” HDD. Before I go buy one, is anyone else doing this?
 
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It seems the best solution (for constant recording) is actually to use a traditional 2.5” HDD. Before I go buy one, is anyone else doing this?
You can also go for a solid state drive. They use a different memory technology to USB sticks. They will also wear out eventually, but take a lot longer. I use a 250GB SanDisk SSD. It's reasonably priced and it has a USB interface already so no need for an adapter.

(It's said that the bigger you go – e.g. 500GB or 1TB – the less the re-writing and the longer it lasts. I'm not sure that sounds correct though. That's why I didn't go bigger than my 250GB)
 
-- Do the math .. 4 MB/second, several minutes of recording. The MCU isnt a huge PC with GB of RAM (its built to a price point), this kind of buffering is expensive (comparatively, I'm not going to argue about RAM costs here), and there are huge demands on memory for more critical things like driving, UI, AI etc etc.

-- Also, if the car were to buffer and then write, it would have to be in catch-up mode when an event triggered, and that might mean overlapping retroactive event flushing with real-time camera data.

-- Finally, these modes are designed for catastrophic event recording. The car might well be disabled within seconds of the event, and these are EXACTLY the kind of events you DO want recorded, so you record everything just in case, then delete uninteresting stuff later. Think flight data recorders in airplanes.

So no, it's not a crazy design. Far from it.


... I'll get my coat ...
 
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You can also go for a solid state drive. They use a different memory technology to USB sticks. They will also wear out eventually, but take a lot longer. I use a 250GB SanDisk SSD. It's reasonably priced and it has a USB interface already so no need for an adapter.

(It's said that the bigger you go – e.g. 500GB or 1TB – the less the re-writing and the longer it lasts. I'm not sure that sounds correct though. That's why I didn't go bigger than my 250GB)

I ended up doing the same. Went with a 500gb Sandisk SSD. $40 on Amazon. So far, so good.
 
(It's said that the bigger you go – e.g. 500GB or 1TB – the less the re-writing and the longer it lasts. I'm not sure that sounds correct though. That's why I didn't go bigger than my 250GB)

Actually this is true. SSD controllers (and better USB flash sticks) use wear-leveling to distribute writes evenly across all the drive blocks. This means (simplifying somewhat) that a drive that is 2x larger will last twice as long when they both have the same amount of data written to the drive. Also, since leveling this is done at the physical drive level, it remains true even if you partition the drive and use one partition heavily for writes (for example, when one contains TeslaCam while the other contains static music).
 
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