NAS Drives: necessary or fluff?

[inkblot14 10]

I've been running a small home NAS system for a few years now. When I first got it, I loaded it with some WD Green drives, and they've been pretty sturdy.

However, one of them is starting to give me SMART warnings and I'd like to replace it before it brings my little RAID to its knees. Looking around newegg, etc., I'm seeing a class of hard drive that wasn't around when I first setup my NAS: NAS and Enterprise drives. WD and Samsung both seem strong here.

I'm wondering, is a hard drive classed as a "NAS Drive" a significant thing? Is there really optimization that helps a drive survive NAS duty, or is it just a label meant to attract customers? Do any NAS owners have experience with this class of drive, and would you recommend it?

Thanks!

[Presjar 10]

I would go with what your budget allows. If the NAS maker says the drive is compatible in the documentation then it should be ok. However, the WD Red drives are good value. Especially because you get a good warranty.

[mumblepins 10]

One main advantage of NAS specific hard drives is that they "give up" trying to read much faster when a bad sector is detected. Standard consumer drives assume a bad sector is the only location of that data piece, so try multiple times in many different ways to read it successfully. However, enterprise or NAS drives in general are part of some sort of redundant array (RAID, ZFS, etc.), and if a sector on one disk goes bad, it's not a big deal, so it quickly marks the sector as bad and rebuilds it from other data. This doesn't slow down the whole array much, and the RAID logic won't mark the whole drive as bad, whereas with a consumer drive the slow down on read time may get the whole drive marked as bad. As Presjar says, the warranty is also part of the cost difference. FWIW though, I've been using WD Green drives without any troubles in RAID array for several years. If super high uptime requirements aren't necessary, you can just tell the RAID controller to have a longer timeout on marking a drive bad, and get away from the problem mentioned earlier.

[Ozric 10]

I have had good luck with WD-Red drives, I have Three 6TB and one 3TB all work good with NAS or as stand alone drives.

[abak007 10]

Hitachi makes some great drives for NAS that have specs for contiunuous operation and that are the same price as the WD green but at higher RPM. I don't think the NAS classification is a necessity but you should probably try to keep drive specs as close to each other as possible.

[KCPTECH 10]

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning/> <w:ValidateAgainstSchemas/> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables/> <w:SnapToGridInCell/> <w:WrapTextWithPunct/> <w:UseAsianBreakRules/> <w:DontGrowAutofit/> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--> Desktop drives are optimized to be fast on seeks. These causes higher seek retries but significantly higher performance. AAM is usually set to moderate levels or disabled. If they hit an error, they'll try very hard for a very long time to get your data back.

NAS drives are optimized to use less power, cause less vibration, spin slower and always have AAM set to high levels, which multiplies rotational latency. They also do not retry forever to get data back, and just try a few times and then report an error.

You can create a desktop drive from a NAS by disabling AAM, although it'll then reach desktop levels of vibration (which you don't care about) or a NAS drive from a desktop drive by maximizing AAM, but you won't get the early retry termination. In RAID-1 you should care about this, as the array may drop a disk for simply taking too long to read.

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