# of cameras and limit writing to 1 hard drive continuously?

[EarlT 0]

WD makes a green drive designed for constant read/write operations. WD10EVDS or WD20EVDS. A little more expensive, but supposedly designed with constant use in mind.

[Quantum 0]

Doing RAID in software is a poor place to start anyway.

But the reality is, {redacted}

Edited May 26, 2011 by Guest

[Soundy 1]

Doing RAID in software is a poor place to start anyway.

But the reality is, 95% of the machines you build will not have real hardware RAID. OK, they say 'hardware' RAID, but that kludge depends primarily on Windows software. It is not hardware RAID.

 

Not the machines *I* build. If I do add a RAID internally to a machine, I use a nice little SiliconImage card that does RAID 0/1/5/10, and yes, ALL IN HARDWARE. The array is created in the card's BIOS, long before any OS is loaded. Windows doesn't even do RAID5 in software unless you get into the server editions.

 

You're obviously a Linux fan, and apparently not that familiar with how things work in Windows these days. I'm not a Windows booster by any means, but do please try to get your facts straight.

 

Remember, I invoked my HTPC to illustrate the reliability of Green drives over time, and for a workout I pointed up my backup/camera servers which get a good workout.

 

Sure the X7SPA mobo has weak video, but that's not needed when it's a network engine to NAS and serve up packets for other machines that have the video hardware.

Nobody's saying green drives aren't "reliable over time" *as such*... the point is, they're not designed for the kind of SUSTAINED use that you see in surveillance DVRs. Your HTPC and home NAS are not a valid comparison to the kind of use an active surveillance system uses, plain and simple. Go to QNAP's website and take a look at their recommended drives for their various models and various uses - you'll note there that not only do they not recommend them for anything beyond SOHO duty, but they specifically recommend *against* them for heavier duty installations, like corporate NAS and surveillance systems.

 

My preference is an external array anyway - QNAP or Enhance Tech, configured RAID6. If I'm going that way, I set the DVR to use the array exclusively for its primary recording target, and relegate the internal drive(s) for "backup" use (system uses them if the array is unavailable). Then if the DVR goes down and I have to swap in a loaner, the video data stays onsite.

[Quantum 0]

Alright. {redacted}

Edited May 26, 2011 by Guest

[thewireguys 3]

@Quantum So yo would feel comfortable using a software only RAID with a 250Mb/s stream of video righting to the hard drives?

Edited May 25, 2011 by Guest

[Quantum 0]

Not to {redacted}

Edited May 26, 2011 by Guest

[skane 0]

WD makes a green drive designed for constant read/write operations. WD10EVDS or WD20EVDS. A little more expensive, but supposedly designed with constant use in mind.

 

I've tested these with high hopes, and they stutter/gap footage. Replaced 'em all with Western Digital Blacks, no stutter/gapping.

[Quantum 0]

Yeah, the {redacted}

Edited May 26, 2011 by Guest

[thewireguys 3]

Not to -a- hard drive, but to a large enough array.

 

WD specs put the 2TB Green at 110MB/s to/from host sustained. Say with spec inflation the true figure is half that. So with zero software overhead you would need an array of 4.6 drives striped, to handle 250MB/s. mdadm overhead has been measured to have a minor effect, so I'd be comfortable with 5 drives in RAID0, or 4 with BTRFS considering spec inflation. But they are going to fill up awfully fast. (Hrm, 10TB = 40,000 seconds = 667 minutes = 11 hours, and reduce for filesystem overhead to say, 10 hours...)

 

Why do you ask? Do you need a solution? I charge for my consulting services...

 

 

No I would never use WB Green for video storage or would I recommend a software RAID for video... Well not if you want anything reliable. Also I said Mb/s not MB/s... BIG difference

[mike_va 0]

Thanks for all the info. I have a WD black I can take out of my Synology NAS, sounds like a good rainy day project.

[Quantum 0]

No I would never use WB Green for video storage or would I recommend a software RAID for video... Well not if you want anything reliable. Also I said Mb/s not MB/s... BIG difference

Welll, that's a shame. {redacted}

Edited May 26, 2011 by Guest

[thewireguys 3]

No I would never use WB Green for video storage or would I recommend a software RAID for video... Well not if you want anything reliable. Also I said Mb/s not MB/s... BIG difference

Welll, that's a shame. I would, and do recommend it.

 

FYI, we are discussing disk storage, and so MB is appropriate. Were it networking then Mb would be. BIG difference, like a factor of ten.

 

 

Well I am glad your not in the IP video business then

 

And no,,,,, I was talking about bandwidth Mb/s you then did your caluations on MB/s

[Quantum 0]

It always comes down to petulance with you no matter what I say, doesn't it thewireguys.

 

[mod edit]

[thewireguys 3]

It always comes down to petulance with you no matter what I say, doesn't it thewireguys.

 

[mod edit]

 

No it comes down to facts and knowing what your talking about.

 

FYI that was totally uncalled for and disrespectful. I am not sure why you enjoy pissing everyone off on this forum but I think is time you should move along.

[Soundy 1]

There's nothing to do with petulance. You're basing all your statements about drive suitability on your experience with home PCs and small home NAS systems. You have several *decades* of combined experience with surveillance systems telling you that your comparisons don't wash, and yet you insist on debating reality and hard-earned knowledge. If anything, Quantum, you're the one being petulant.

 

Simple fact, folks: regardless of what manufacturer specs and marketing tell you, nearly every pro here HAS actually TRIED "green" drives in surveillance systems and found that THEY DON'T WORK WELL.

 

Go into a forum populated by automotive engineers and tell them any number of bizarre "fuel-saving devices" you can buy off TV will work to improve their gas mileage, and you'll get pretty much the same kind of response.

[Campbell 0]

WD makes a green drive designed for constant read/write operations. WD10EVDS or WD20EVDS. A little more expensive, but supposedly designed with constant use in mind.

 

I've tested these with high hopes, and they stutter/gap footage. Replaced 'em all with Western Digital Blacks, no stutter/gapping.

 

I'm just going to put it out there that I've "NEVER" had any issues with Green drives. No read or write issues period.

 

Of course, I pretty much exclusively use megapixel IP cams, but I wouldn't think that would make a noticeable difference. And this is from anything from a singular 2TB drive to a 20TB array (which has been going almost 2 years without issues).

[rory 0]

I had a WD Green, spent 2 weeks trying to figure out why my DVR's recordings were jumping, skipping, while the system worked fine - changed the mobo even with no luck, ran full tests on the HDD and it was fine - in the end i connected a 5400rpm USB drive and used that instead, problem went away - so I got rid of that green drive quickly and replaced with a WD Blue drive, problem fixed.

 

So whether the greens will work or not (i HAD to put one in a Dahua for a client as was the only 2TB I could get locally at the time and it DOES work, 7fps though so who really knows), I would not suggest it, but maybe others have more time to troubleshoot than I do.

[tomcctv 187]

many companys are now putting into there specs not to use green drives they just dont work WD even now have a statement green drives are not warranted on dvr use. (100s of people sending back, WD finding no faults) some HDrive manufatures even say not to use AV HDrives for DVRs they are designed for PVR were they are stopping and starting all the time .... which DVRs dont.

[junkjunk13 0]

I have 1 synology 1010+ with 5 WD Greens in RAID 6. I use it to mainly to store my BR movies. I don't compress the BR movies so when I stream them we are talking about +25GB per movie.

I used WDTLER and WDIDLE on my WD Greens and have no problems at all with constant streaming from my SAN.

 

But yes they are not professional/enterprise. So if you are a company or such I would indeed not use WD greens as well.

[thewireguys 3]

I have 1 synology 1010+ with 5 WD Greens in RAID 6. I use it to mainly to store my BR movies. I don't compress the BR movies so when I stream them we are talking about +25GB per movie.

I used WDTLER and WDIDLE on my WD Greens and have no problems at all with constant streaming from my SAN.

 

But yes they are not professional/enterprise. So if you are a company or such I would indeed not use WD greens as well.

 

Streaming BR movies does not even come close recording video streams. Keep in mind when you are recording video to hard drive we are reading, writing and deleting at the same time.

[Soundy 1]

many companys are now putting into there specs not to use green drives they just dont work WD even now have a statement green drives are not warranted on dvr use. (100s of people sending back, WD finding no faults)

Interesting... I've pulled a couple of 2TB WD Greens out of a RAID that threw errors saying the drives were failing... replaced them with Blacks... still have the Greens sitting on a shelf. I should test them... hmmmmm!

[hardwired 0]

many companys are now putting into there specs not to use green drives they just dont work WD even now have a statement green drives are not warranted on dvr use. (100s of people sending back, WD finding no faults)

Interesting... I've pulled a couple of 2TB WD Greens out of a RAID that threw errors saying the drives were failing... replaced them with Blacks... still have the Greens sitting on a shelf. I should test them... hmmmmm!

 

The reason the drives show as failed in a RAID array, especially true hardware RAID, is that the green drives, (and some other desktop drives, too), are designed to spin down after a period of non-use, which happens often in a RAID array. If the drive doesn't spin up fast enough when needed, the controller marks it as failed.

 

Check the event log of a system using green drives like that, you'll see lots of drive lost/drive reappearing messages.

 

The other problem with some green/desktop drives is the lack of TLER (Time Limited Error Recovery), which means if a regular drive finds an error, it will spend too much time trying to fix itself, and the controller will mark it as failed.

 

RAID-specific drives limit the amount of time they spend trying to fix themselves, counting on the controller to find and fix errors instead.

[Soundy 1]

Interesting... that might explain the four 1TB Seagate drives I've pulled out of another array over the last couple years, all of which the RAID said were failing, all of which have benched fine even after "long", zero-write, and burn-in tests.

[hardwired 0]

Interesting... that might explain the four 1TB Seagate drives I've pulled out of another array over the last couple years, all of which the RAID said were failing, all of which have benched fine even after "long", zero-write, and burn-in tests.

 

They'll work fine in your HTPC

[skane 0]

The reason the drives show as failed in a RAID array, especially true hardware RAID, is that the green drives, (and some other desktop drives, too), are designed to spin down after a period of non-use, which happens often in a RAID array. If the drive doesn't spin up fast enough when needed, the controller marks it as failed.

 

Check the event log of a system using green drives like that, you'll see lots of drive lost/drive reappearing messages.

 

The other problem with some green/desktop drives is the lack of TLER (Time Limited Error Recovery), which means if a regular drive finds an error, it will spend too much time trying to fix itself, and the controller will mark it as failed.

 

RAID-specific drives limit the amount of time they spend trying to fix themselves, counting on the controller to find and fix errors instead.

 

Good point, and to add to this, WD Blacks (up to "late" 2009) could have TLER enabled to make them work more reliably in arrays. The newer (post-2009) WD Blacks supposedly can't have TLER enabled. Haven't tried it myself, since I don't run my WD Blacks in arrays (I run the WD REs in arrays).