Pre-event recording to SD card

Discussion in 'Dahua' started by wopi82, Nov 5, 2018.

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  1. wopi82

    wopi82 Getting comfortable

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    Hi all. I’ve been using Dahua cams for a 1.5 year now, and I’m pretty happy with this equipment. There is however one thing that is bothering me. I use my cams only with micro SD cards. It makes the system as simple as possible. Every cam is powered by separate 12V UPS, which makes every cam “self sufficient”, even in case of power shortage or network failure. I use motion detection for recording. However there is an option in Record control called Pre-event record. It means the camera is actually recording all the time, 24h/7 days a week, and leaves only moments, when event occurs, plus prerecorded period. And so, the micro SD card is under constant usage, even if nothing is happening. After a year or two, such card is dead no matter what. Now the question: if I set the pre-event recording time to 0 seconds, will the camera stop the process of constant recording? Can someone please confirm that?
     
  2. bug99

    bug99 Getting the hang of it

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    I can not confirm the question. What i can say is that of the 10 or so cameras that i have that record 24/7 to the uSD card, none have failed in 2 years (knock on wood). I use the 128GB Samsung Evo drives. i get about 3 -4 days before overwrite. I believe this class of drive is rated at 1 write per day for 3 years, or based on my pattern 10 years. I should therefore see one fail per year in my set of 10, so i guess i am doing well.
     
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  3. Dave Lonsdale

    Dave Lonsdale Getting the hang of it

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    Mmm.... I have around 10 Dahuas that are over 4 years old recording motion events to SD cards nights and weekends (as well continuously to BlueIris 24/7). Maybe no failures is just luck. Remind me how to find the cameras' Pre-event setting.
     
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  4. wopi82

    wopi82 Getting comfortable

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    Ok. Maybe I wrote it incorrectly. The cards are not dead, but lot of errors occur. Some files are unreadable or choppy (lot of dropped frames). I use 64GB Sandisk Ultra A1 class micro SD.
     
  5. bugsysiegals

    bugsysiegals Young grasshopper

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    I’m getting some new cameras soon and will likely put up my first camera before I have my PC up and running. That said, what’s a good SD card to use for motion events? I was able to buy buy 64GB micros for $20 each last Black Friday so it would be nice to know what my best bet is.
     
  6. Jedi2020

    Jedi2020 Young grasshopper

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    I only use u3 class 10 sd card after experiencing drop frames with u1 class 10 card. u3 cards from Sandisk and Samsung are very good based on my own test. And watch out for counterfeit cards from eBay, especially the ones selling for unusually cheap. I caught one after testing it. Fortunately, the seller refunded my money after sending it back.
     
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  7. Jedi2020

    Jedi2020 Young grasshopper

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    U3 class 10 cards from Samsung and Sandisk are very good. Look out for cheap counterfeit cards from eBay. There are simple utilities available on PC to test the performance of the card. I always run them to test my newly purchased sd card.
     
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  8. bigredfish

    bigredfish Known around here

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    another vote for 128GB Samsung Evo
     
  9. bugsysiegals

    bugsysiegals Young grasshopper

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  10. ernesto1208

    ernesto1208 n3wb

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  11. looney2ns

    looney2ns Known around here

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  12. bugsysiegals

    bugsysiegals Young grasshopper

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    Ouch, a day late. I’ll keep my eye out on future sales of these.
     
  13. ernesto1208

    ernesto1208 n3wb

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    Last edited: Nov 7, 2018
  14. SouthernYankee

    SouthernYankee Pulling my weight

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    Ernesto... That will work. Record direct to the SD card.
     
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  15. ernesto1208

    ernesto1208 n3wb

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    from my understanding I would just need the switch with poe to power them
    I was eyeballing this budget switch Tenda 5-Port PoE 10/100 Switch
    4 ports have poe
     
  16. looney2ns

    looney2ns Known around here

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    Yes
     
  17. Jedi2020

    Jedi2020 Young grasshopper

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    The only way to confirm is to run the simple utility like H2testw to see the read and write performance. It takes seconds to find out. For u3 card, you should get 90MB or higher for read and 30MB or higher for write. A counterfeit will do under 15MB.
     
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  18. bugsysiegals

    bugsysiegals Young grasshopper

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    Sweet!! Thanks for sharing that!!
     
  19. looney2ns

    looney2ns Known around here

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    It doesn't have to come from Ebay to possibly be fake.
    Retail stores have fallen victim, Amazon has sold counterfeits, most likely, unwittingly.
     
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  20. bugsysiegals

    bugsysiegals Young grasshopper

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    I will receive mine today and confirm ... TBD
     
  21. bugsysiegals

    bugsysiegals Young grasshopper

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    The Evo Select is supposed to read/write at 80/20 Mbyte/s and I'm running H2testw which is showing write speeds of about 67-72 Mbyte/s. What should a good speed be?

    Possibly goods news is I read the Samsung Evo Select is the same as the Evo Plus and is just re-branded for exclusive sale by Amazon.
     
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  22. bugsysiegals

    bugsysiegals Young grasshopper

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    Down to 66 Mbyte/s after 30m of writing.
     
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  23. bugsysiegals

    bugsysiegals Young grasshopper

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    Warning: Only 122079 of 122080 MByte tested.
    Test finished without errors.
    You can now delete the test files *.h2w or verify them again.
    Writing speed: 66.2 MByte/s
    Reading speed: 80.4 MByte/s
    H2testw v1.4
     
  24. bugsysiegals

    bugsysiegals Young grasshopper

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    seems faster than the specs say it should be?
     
  25. bugsysiegals

    bugsysiegals Young grasshopper

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    Should I buy more of these while they're on sale? Will these last without being "high endurance" cards?
     
  26. Jedi2020

    Jedi2020 Young grasshopper

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    Your result is similar to my Samsung Select. So you got a legit card.
     
  27. Jedi2020

    Jedi2020 Young grasshopper

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    Correct. They both produced similar result if I remember correctly. So buy which ever one is cheaper.
     
  28. bugsysiegals

    bugsysiegals Young grasshopper

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    The price is right and seems to be a good card so I'll be picking up more and of course testing them in case I need to return any.