WD 3TB Caviar Green drives - Raid 5?

thepregnantgod

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What is the community's opinion on using 4x3TB on a RocketRaid 2300 Raid 5 configuration? I would primarily use it as a media server - reads over an ethernet connection - writing speed not a priority.

I know the speed is 5400rpm but it has a 64MB cache, good reviews and would be hosted by an i5 2500K @ 4.5ghz with 16gigs RAM.

Final question: Would Raid 5 in this situation be faster or slower than an individual drive?
 
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RR2300 series is middle raid card, it also call hardware assist, all the calculation is performed by host CPU, if you have a dual core then it should be no problem at all.

Look at my 180W power consumption 40TB media server here

All the...

tokencode

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Writing will definitely be slower on RAID 5, but if you're primarily concerned about reads and space RAID 5 will work. A BBU won't make any difference as far as speed goes, it will just protect you against data curruption in the event of a power failure. If you are using write cache (which will inprove write speed) a BBU is HIGHLY recommended.
 
Though I wouldn't necessarily do it, it's acceptable if the system and the UPS are properly configured (shutdown the system before the batteries are completely discharged and don't allow the UPS to provide power until the batteries are recharged to the point where normal operation can be resumed).
 
It will be faster for reading, much slower for writing. Also note that RAID-5 does not improve access times, only (for reading) transfer rates - that means a RAID-5 array made up of 5400-rpm drives will have longer access times than even a single 7200-rpm drive. That's important if the kind of performance you're trying to optimize is lots of small I/Os, such as booting or starting up programs.

It's important to understand that RAID-5 can be of questionable value for large volumes depending on the unrecoverable read error rate of the drives you're using. Many drives have an unrecoverable read error rate of 1 error per 10^14 bits read. A 10TB array has around 10^14 bits. That means if you loose a drive you have roughly even odds of encountering an unrecoverable read error, in which case the array won't be able to rebuild and your data will be toast. What's the point of using a redundant RAID organization if half the time it won't work? RAID-6 is a much more robust approach for handling large volumes, but unfortunately it's not supported by most motherboard RAID implementations (and it's complex enough that it's probably best left to a hardware RAID controller).
 

thepregnantgod

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Do you guys know is there's a way on the WD drives (like Seagate) to change the "spin down" settings on these green drives? I'm already hooked at 4 3TB drives - my only choices now are to run them individually or in Raid 5. I like the redundancy and increased read times as well as an individual volume for management.

I'm using a Highpoint Rocketraid 2300 which is really a fancy software raid - but the reviews state that cpu usage is at most 3-5% and I have a lot of leeway in that area.

 
May I suggest you contact WD as they should be able to answer your question. Since they normally spin between 5400 and 7200 RPM, it means that spindle synchronization probably is not possible. They definitely are designed to achieve minimum power draw, but they are not well suited for RAIDs.
 

FireWire2

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RR2300 series is middle raid card, it also call hardware assist, all the calculation is performed by host CPU, if you have a dual core then it should be no problem at all.

Look at my 180W power consumption 40TB media server here

All the HDD are WD green drive, about a yr w/o a problem
 
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ruby2010

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NullDevice

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With the latter one i agree. And i normally also like 10 better than 5, dependent on the situation...
But why should he use "RAID 10 since its not a hardware raid"? Hardware-RAID must be slower than CPU driven RAID. Or do u think even a controller around 1.000 $ comes close to the power of a modern dual or quadcore CPU? Anyway i also like Hardware RAIDs better coz i think they r more stable when the OS breaks for some reason. Hard to recover most of the software raids when u have to boot it from another OS or media.

And to come back to the original topic:
Im also thinking at the moment to buy some of those drives, WD green 3TB. I would never ever use them in my work, im free to order good but expensive ones there. But for my home server for personal use, i would buy 4 of them, possibly for a RAID 10 or 5. Ive an adaptec 5045 controller.

I wonder how all the controllers react to 4k advanced Format. Any1 know if they can handle that?
Also pretty disappointing: i heard of a friend who worked with those drives, that they had quite often unrecoverable errors.
Hmmm...
 

thepregnantgod

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The thread is a bit old but I feel obligated to report my results. I wanted to come back and say, "Ha, ha, ha..." to all the naysayers about using 3TB Green drives in RAID. Alas, I'm not saying that.

I had 4 3TB WD Green drives in a RAID 5 format attached to a RocketRaid 2300 card. Despite all the advice that green drives have such a problem with TLER I thought I would do it anyway. I moved all 6 TB of my movies to the array. In my mind, even if one drive failed I could still operate, albeit slowly, because it was in a RAID 5 array. I would simply pull the bad drive and rebuild. (Additional note, I thought since the RocketRaid 2300 is fake raid at about $120 it wouldn't have the same problems that real RAID controllers do...got that from some post)

I lost all my movies.

A few days ago the A/C went out upstairs and the hard drives started dropping. So I took the system downstairs where our other A/C unit was working and proceeded to rebuild. The problem is that rebuilding a RAID 5 array composed of 3TB drives takes days and days. It has to read every bit of data. Thus, within that time another drive would always drop. I'd have to reboot and then start over. After trying to save my data for over 5 days, the RAID simply wouldn't read the drives anymore.

So, to anyone searching for WD 3 TB drives in RAID - DO NOT ATTEMPT.
 

thepregnantgod

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No. I had to return one drive - failed bad sectors and wouldn't repair. The others are fine. I'm using them as individual drives in Legacy format attached to the RAID controller.

As for the backups, my backups are the original movies. I just have to put them all back on the drives.
 

AbuSous2000

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When you have used WD Green in RAID 5, did you disabled the parking/idling time vi WDIdle3.exe utlity? I have the same configuration running fine for 3 months under heavy usage