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Is mixing enterprise HDDs and desktop HDDs in a NAS a bad idea? (Trying to transition a NAS to all enterprise drives without the large one off cost by instead replace the desktop drives with enterprise drives as they fail)

Edit: Just to clear up some of the questions below, as I was admittedly rather vague. I am referring to SATA "Enterprise disks" e.g. Seagate Constellation ES.3 ST2000NM0033 vs. their desktop counterparts E.g. Seagate Barracuda ST2000DM001. Would mixing these types of disk cause problems? From the looks of the replies, yes. I will also ask the NAS manufacturer but I wanted an independent/second viewpoint.

The NAS is a RAID 5 array with 8 disks (1 is a cold spare).

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Yes. Does anyone even make enterprise SATA drives anymore? –  HopelessN00b Feb 13 '13 at 15:40
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Got SATA in two HP ML110 G7 right next to me. They're for small branch offices, mind you. –  mfinni Feb 13 '13 at 15:58
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What NAS make/model are you talking about? –  ewwhite Feb 13 '13 at 16:30
    
8 2TB drives in a RAID 5 is dangerous. You should read up about UREs and large RAID 5 arrays. –  MDMarra Feb 14 '13 at 11:32
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3 Answers

What exactly are you talking about? Enterprise drives are typically SAS, and though SAS controllers can support SATA disks, SATA controllers cannot support SAS disks. If you got a SOHO NAS, then you probably cannot put SAS disks in it at all.

If your NAS only supports SATA disks, you can't mix and match SAS/SATA at all. If your NAS does support SAS and SATA, then it's fine to mix them in different arrays, but I've never seen a manufacturer that supports SAS/SATA in the same array. They're two totally different protocols.

Now, if by "enterprise" you mean something like a WD RAID Edition, which is a SATA disk that has a higher than typical MTBF and supports TLER, then support for mixed arrays with something like that is generally up to the NAS vendor. Call them and find out. I'd guess that most sysadmins wouldn't consider disks like this to be truly enterprise-grade though, despite their name.


As an aside, usually it's cheaper to have a large "one off" cost, because you can get a discount by buying in bulk. You'll find it's usually substantially cheaper to buy 12 disks all at once rather than making 12 individual transactions. Just food for thought.

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Its a tradeoff - buying all your drives at the same time makes them more likely to fail at the same time though. Also Black is more a performance drive, Raid Edition is more suited to a NAS –  JamesRyan Feb 13 '13 at 16:08
    
My mistake, I thought that the Blacks were the RAID edition. You can tell that I don't keep up on the SATA market. I've edited my answer :) Also, with a proper warranty, which I'd assume someone has if they're buying enterprise equipment, when something dies isn't as important. As long as you have a sane RAID level and hot spares, the odds of a handful of disks dying before you can rebuild is low. Especially in RAID levels that can sustain multiple failures. Of course, this all depends on the configuration that the OP is using, which isn't mentioned at all. –  MDMarra Feb 13 '13 at 16:09
    
Black is for performance, Green is more power-efficent and Red is for NAS drives. Black and Red disks tend to cost more than green ones. –  tombull89 Feb 13 '13 at 16:12
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Mixing within an enclosure, no problemo. Mixing within an array, bad idea.

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You can't neccsarily mix SAS and SATA on the same backplane regardless of controller support. –  JamesRyan Feb 13 '13 at 16:09
    
He never said anything about SAS; nor did I. –  Chris S Feb 13 '13 at 16:11
    
Well then you would be just wrong because there is no reason preventing someone from mixing any SATA drive with another in a single array! Mixing performance might be suboptimal but enterprise drives, don't typically perform any better, just have higher reliability ratings. –  JamesRyan Feb 14 '13 at 15:48
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Some SATA hdd have enterprise verison. I don't agree MDMarra 's point.
you can get the info from http://www.wdc.com/en/products/internal/enterprise/

I have same question too ,I compare WD10EZEX-00RKKA0 and WD1003FBYX-23.
In Linux, I used "hdparm" to show all feature.they have some different feature.

WD1003FBYX-23 support and WD10EZEX-00RKKA0 not support
* WRITE_UNCORRECTABLE_EXT command
* SCT Error Recovery Control (AC3)
* Idle-Unload when NCQ is active
* Advanced Power Management feature set
* SCT Long Sector Access (AC1)

WD1003FBYX-23 enable, WD10EZEX-00RKKA0 disable, I don't know how to enable it for WD10EZEX-00RKKA0
* DMA Setup Auto-Activate optimization

  • WRITE_UNCORRECTABLE_EXT command you can get info from hdparm man page, "--make-bad-sector" need this function support.
    it 's look like just for test.

  • SCT Error Recovery Control (AC3)
    Desktop hdd have no the function, In raid environment, the hdd always very busy, the raid controller can 't receive the respond from this hdd. if timeout, the controller will delete the hdd,and raid volume status will switch to "rebuilding". I guess there is another variable for monitor enterprise hdd health. I don' t know how to make sure.

You can get info from http://knowledge.seagate.com/articles/en_US/FAQ/203991en?language=en_US
I think it 's import different from enterprise hdd to desktop hdd.

  • Idle-Unload when NCQ is active
    --idle-unload (hdparm man page)
    Issue an ATA IDLE_IMMEDIATE_WITH_UNLOAD command, to unload or park the heads and put the drive into a lower power state. Usually the device remains spun-up

  • Advanced Power Management feature set
    More powerful Power Management feature. You can search "hitachi Hard Disk Drive Specification" for get more info.

  • SCT Long Sector Access (AC1)
    I don 't found anything about "SCT Long Sector Access". Anybody could tell me ?

Now, for reduce the cost,I try replace some desktop hdd in some archive server(DAS),because archive server loading is steady.

I suggest you 'd better compare with your desktop HDD, There is no another custom or newer feature to be used in your NAS raid controller and NAS OS.

I am not recommending use desktop hdd in NAS.

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