Hard drive question

[Supernaut 0]

I'm about to purchase and Dahua DVR and have a question about the hard drive since I can't seem to find the info I need. I would assume this uses a 3.5" hard drive, as would most dvr's in general?

 

And what about the SATA number, SATA II SATA III... etc?

[tomcctv 190]

hi. i would go with buying HD already installed ...... best going with manufatures recommended HD

[Soundy 1]

Standard 3.5", pretty sure they're all SATA II (FYI, SATA I/II/III are all cross-compatible). Main thing you want to keep in mind is to avoid "green" drives; even "A/V" drives aren't generally that well-suited to surveillance usage. High-end desktop or enterprise-grade drives are recommended, like the Western Digital Caviar Black or RE4.

[Supernaut 0]

Good advice. Just to further my education. What are "green" drives and "a/v" drives?

[Soundy 1]

 

Most manufacturers have models that are designed to be more energy-efficient, sometimes running cooler and/or quieter... problem is, they're designed to spin down on occasion to save power, and that can cause intermittent breaks in access - not good when you're reading and writing constantly as you likely will be with multiple cameras. There are lots of reports in threads here about this causing stuttering or drop-outs in video.

 

A/V (audio/visual) drives are a bit better, usually designed for higher-volume uses like home PVRs (TiVo, etc.) and home theater PCs... but again, are not so much designed for the sustained read/write levels that a surveillance DVR sees.

[Supernaut 0]

That clears up the diversity of hard drive options I see out there. I notice the green drives are cheaper but that has to be because of the lower RPM they operate at.

 

Are Hitachi or Seagate any good? I can get a good price on a 1 TB 7200RPM Hitachi drive locally.