Buying Some HDD for CCTV DVR

[Imminent]

Hello,

Maybe someone can assist me

I'm planning on ordering some devices for our company from esquire because of the benefit of a lower price and dealing direct with the distributor.

We will be buying 1Tb hard drives for use in our 3 DVR machines at work.

I suspect we will purchase around 6 of these drives. My DVR states it supports SATA2 so I can probably buy any old SATA2 hard drive.

My choices are:

Samsung SATA2 1TB 7200RPM 32MB HDD
Hitachi GST Deskstar 1.0TB *Serial ATA Hard Drive (SATA 3Gb/s, 7200rpm, 32MB Cache)
Seagate Barracuda*1.0TB*Serial ATA Hard Drive (SATA 3Gb/s, 7200.12, 32MB Cache) ~ New

I'm leaning towards the Samsung since I've previously owned such a hard drive and I didn't give me much problems, but this was an 80gig sata2 drive. I must confess I am not clued up with all the latest tech so if you could advise me on which brand would be the best / most reliable I would greatly appreciate it.


Regards

 

[Drunkard #1]

I'm in the exact same position right now, why aren't you looking at Seagate SV35 drives? They're allegedly customised for 24/7 DVR work. Sorry I can't be more helpful, I'll let you do the research and then copy it. BWA HA HA HA HA HA.

 

[Imminent]

I'm in the exact same position right now, why aren't you looking at Seagate SV35 drives? They're allegedly customised for 24/7 DVR work. Sorry I can't be more helpful, I'll let you do the research and then copy it. BWA HA HA HA HA HA.

i see

 

[xplicet]

Check that your DVR manufacturer is happy with the various brand HDD's. Avermedia for instance is VERY fussy about what HDD's it uses. Certain DVR manufacturer only offer support on machines with "supported" harddrives. The Seagates SV35's mentioned above are highly recommended as they are designed for constant righting. Very expensive though!

 

[Drunkard #1]

Check that your DVR manufacturer is happy with the various brand HDD's. Avermedia for instance is VERY fussy about what HDD's it uses. Certain DVR manufacturer only offer support on machines with "supported" harddrives. The Seagates SV35's mentioned above are highly recommended as they are designed for constant righting. Very expensive though!

So they're not just hype? Because they're not that much more than the barracudas, NGR has them for R 787 for a 1 TB drive. I need to get my video server outputting a decent picture before I look at recording hardware. I was thinking of an Intel board with onboard RAID and some recording application (zone minder?). Do you think they'll be suitable for that too?

 

[xplicet]

So they're not just hype? Because they're not that much more than the barracudas, NGR has them for R 787 for a 1 TB drive. I need to get my video server outputting a decent picture before I look at recording hardware. I was thinking of an Intel board with onboard RAID and some recording application (zone minder?). Do you think they'll be suitable for that too?

Normal hard drives dont spend all of there lives writing so they are not designed for constant read write. The SV35's supposedly are. I started seeing alot of standard HDD failures in DVR's when we started deploying higher capacity (500GB+). Id the days of 250GB and smaller we hardly ever had problems. I haven't used hundreds of SV35's but I am yet to have one single problem with any of them installed thus far. Sounds like pricing has dropped nicely!

With regards to better image from vid server and recording software; you'll have to let me know more about your equipment and environment. What cams, what DVR/Vid servers, what hardware etc You can PM or carry on via this discussion.

 

[Gnome]

Normal hard drives dont spend all of there lives writing so they are not designed for constant read write.

I disagree:

A 2007 study published by Google suggested very little correlation between failure rates and either high temperature or activity level

Furthermore the act of reading and writing data does not cause wear. Wear is caused by the movement of the load/unloading of the heads (doesn't occur during reading/writing). Read/writing consists of the head moving into place and the magnetic polarity being read or changed, neither of which wears out a disk drive. The wear on a disk is caused by the moving parts wearing out. The amount of wear before failure is governed by the mean time before failure (MTBF), more from wikipedia:

The mean time between failures (MTBF) of SATA drives is usually about 600,000 hours (some drives such as Western Digital Raptor have rated 1.4 million hours MTBF),[70] while SCSI drives are rated for upwards of 1.5 million hours.[citation needed] However, independent research indicates that MTBF is not a reliable estimate of a drive's longevity.[71] MTBF is conducted in laboratory environments in test chambers and is an important metric to determine the quality of a disk drive before it enters high volume production.

Google has completed an large study on the subject matter, and I believe that their research concludes that many of these assumptions and many of the claims by manufacturers are fallacies.

For example: RAID edition drives come with certain settings changed. When a hard-drive usually encounters a sector it cannot read, it will attempt to recover for up to a minute. On a RAID edition drive this recovery time will be set very low so that the drive is not dumped from the array as having become unresponsive. Furthermore those drives also come with longer warranties or feature extra SATA commands (eg. NCQ). For that you pay a hefty price.

Furthermore the belief that a HD must run cool is false:

A common misconception is that a colder hard drive will last longer than a hotter hard drive. The Google study seems to imply the reverse—"lower temperatures are associated with higher failure rates". Hard drives with S.M.A.R.T.-reported average temperatures below 27 °C (80.6 °F) had higher failure rates than hard drives with the highest reported average temperature of 50 °C (122 °F), failure rates at least twice as high as the optimum S.M.A.R.T.-reported temperature range of 36 °C (96.8 °F) to 47 °C (116.6 °F).[68]

My advice, buy the cheapest drive that will suit your needs AND is supported by the manufacturer. While keeping that in mind I'll share some of my own personal experience with you:

I run a NAS and I've setup a few others. If you are planning on running 6 drives in a single unit, then buy low power drives! I currently run a 6x2TB drive NAS with low power 3.5" drives and the heat output is quite high. At idle these hard-drives sit at 40 degrees, under load the go up to 46. That is with the case open and a fan blowing on them.

Also, some of the newer large capacity drives feature something called advanced format, where the sector size has changed. Trust me on this, DO NOT buy an advanced format drive UNLESS the manufacturer EXPLICITLY says otherwise. It's a long story but those drives can have SIGNIFICANTLY reduced performance if not supported (write speeds on a WD Advanced format with unsupported device is 4mb/s VS the normal 80mb/s if supported. Not sure if I should point out that 4mb/s is unacceptable).

Lastly, BEWARE of Seagate. Even some of the newer models feature firmware bugs, not just the 11 series. For example the new Seagate LP (low power) drives also have a firmware bug. Personally I think for low power Western Digital Green Power is the best. Just be careful because the WD EARS drives (eg. WD20EARS is a 2 terabyte drive with 64mb cache) IS AN ADVANCED FORMAT DRIVE! Rather get the WD20EADS instead, or etc.

Some of the new Samsungs sold by Esquire are ALSO advanced format (4kb sector size instead of 512k sector size).

 

[Drunkard #1]

Aren't those the same studies that 'prove' that enterprise drives are no more reliable than desktop drives? Have they tested 500GB+ drives, because anecdotal evidence seems it indicate that these high capacity desktop drives are extremely unreliable. The other obvious comeback is, "Why would Seagate put all the effort into developing enterprise and niche market drives, if a barracuda suits all applications?"

As far as I'm concerned, xplicet's personal experience is the most reliable data I've managed to obtain comparing 1 TB barracudas with SV35s. There just aren't any independent studies comparing a wide range of common drives in typical use. I'm not saying that Google's tests were wrong, but they just struck me as fishy (and this isn't the first time I've looked at them); something about them doesn't correlate with most people's experience and gut feel (I've learnt to trust my gut).

This obviously doesn't just apply to CCTV. A lot of us would like to set up a small (expandable) NAS, and just don't know which way to turn - RAID or no RAID, dedicated card, onboard or software raid, hot spares or not, LP drives or standard drives. And that's just the hardware, what about the OS... AND BACKUPS...

Anyway, for an extra hundred bucks, I can't see the harm in installing SV35 drives over barracudas. I still trust Seagate not to release rebranded barracudas as 'DVR drives' without some optimisation.

Edit: I just reread the Google study, and can confirm that it presents no useful data. Temperature and usage is not significantly user controllable, the study doesn't look at 500GB+ drives, and it really is useless without the "proprietary information" that the authors withheld, namely, the manufacturer and model specific failure data. Sorry, but that study failed to impress the first time I read it, and nothing has changed.

 

[Gnome]

@Drunkard #1: The Google study alone isn't the only one there. The reason you haven't seen many studies is because conducting such a study isn't something just anyone can do. I don't know if you know this but Google has a massive amount of servers, apparently more than a million.
This is the setup of a Google server: http://news.cnet.com/8301-1001_3-10209580-92.html

They are therefore in a good position to do such research, more than a million hard-drives from which to extract S.M.A.R.T data to do comparison.

Also you are assuming that Seagate actually spend money developing an "enterprise" drive. I don't disagree that higher capacity drives will have higher failure rates, that can be logically deduced as the hard-drives have more moving parts. Naturally it's up to you to trust whomever you want. If you are naive enough to trust a corporation, well that is your prerogative.

But I'll pose this question to you:
How does a DVR wear out a drive more than a PC? Why does constant reading/writing wear out a drive more?

You do understand that the drive is a huge magnet. The magnetic platter cannot be worn out. I'll further say that moving around the read/write heads don't really cause much wear. However the loading and unloading of the read/write head does cause wear (hence there is a S.M.A.R.T value tracking the amount of load/unloads).

 

[xplicet]

Interesting debates from all round. I just go on experience. I firmly believe heat does play a roll on drives as I have had constant failures with towers containing 3 or 4 stacked drives with limited air movement. When changing chassis or layout the failures disappeared.

 

[Gnome]

@xplicet: How hot are we talking? If the drives were run outside of specification I wouldn't be surprised. Remember most drives have a 50 - 55 degrees Celsius limit. The Google study did not go above 50 degrees average. Might be average but hard-drives don't wildly fluctuate in temperature so I believe it is fair to assume those drives never went above 55 degrees (if even that high).

That said, how many hard-drives do you have running lower than the recommended temperatures? In SA running a drive below 36 degrees isn't usually possible except in winter, and then only if you have incredibly well ventilated system with cold air constantly coming in (hardly server room environment). Even with single drive setups with a 120mm fan blowing on the drive I've never had 3.5" drives run lower than the recommended minimum temperature.

But what they say about temperatures does make sense to me however. It's the same with cars, you cause more wear the first 15km of your journey to Cape Town (from Pretoria), than the entire trip there. Bearings and oils are designed to operate in a very tightly controlled temperature band. When you move outside of that band (especially colder), wear increases exponentially. Bearings are especially vulnerable because oils have trouble flowing at low temperatures and bearing failure is almost always caused by lack of lubrication.

 

[Drunkard #1]

I know the Google study isn't the only one, I've seen a few, but they're all useless without manufacturer and model specific data, which is impossible to obtain reliably outside of a huge corporation. Also, they need to be updated for modern drives; like I said, anything over 500GB seems to be 100 times more likely to die, than 'old' sub 500GB drives.

I also agree with the temperature advice - use 1 constant speed fan to keep drives within a reasonable temperature range, one of those studies showed that the thermal shock of a variable speed fan kicking into high speed damages drives more than high heat does.

As for the increased use of DVR drives, well, my PC spins down from roughly 8pm to 6 am, so that has to extend it's drives lives. It's not like I'm spinning down the drives for an hour at a time. A DVR drive must run 24/7, and not just spin, but record data. That is different from my desktop's usage, so it's understandable that the drive should be different. Like I said, the studies are absolutely useless, so the only data we've got is users' experience.