Where to buy drives (and possibly which types)?


ctviggen

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I need at least one 3TB drive to match one of my two parity drives (I'll be replacing it with my 3TB hot spare/cache).

 

I've bought from NewEgg and Amazon in the past. Searching at Amazon, there's an overwhelming amount of information.  The "cheap" drives appear to be refurbished/used.  The "medium price" drives appear to be suspect in terms of warranty:  possibly "OEM" drives without warranty for someone like me (an individual).  I can't tell which drives are "real".  (And I have used the warranty in the past to replace a drive that failed.)

 

And you don't want to read reviews, as they are all over the map.

 

So, do I just order "something", without regard to price?  

 

Any place that's recommended (if Amazon is not the best place)?

 

And I used to buy WD "green" drives, which appear to no longer be made.  I know I don't need "fast" drives, but do I need "NAS" designation?  WD red? Another manufacturer?

 

Thanks.

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You might consider replacing parity with a larger drive and reusing parity as a data disk. That way you will be able to use larger drives in your array, whether as replacements or in new data slots.

 

8TB seems the be the sweet spot at the moment as far as TB per dollar.

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I'd agree with Turl and look at replacing the parity drive as part of the upgrade path as lower capacity drivers are disproportionately expensive and you'll then get a significant uplift in capacity with fewer spindles later on.

 

I'm now up to 5 x 8TB drive shucked from external drives. They are all ~ 5200rpm He8 drives so I assume they are Hitachi rebadged to WD.

Hitachi He drives did pretty well in the most recent backblaze data.

 

The My Book and Elements external drives contain EZAZ or EMAZ drives at least in the EU and are often on sale at very reasonable prices, at least compared to any retail bare 8TB drive.

 

If you do go for WD drives, be careful with the Blue label (as found in 6 TB and below external drives) as they contain the aggressive head parking so rack up huge Load Cycle counts. I've temporarily removed a 4TB drive that clocked ~800k load cycles in 9 months (life time spec 300k) though I also have a 3TB Green drive that got to 1.5m load cycles before I spotted it and that is still going strong nearly 12 months later. I was able to disable head parking on the green but I can't on the blue as it has later firmware.

 

 

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@ctviggen I agree with the above comments.  If I were you, I would get an 8TB in an external enclosure, shuck it and do the parity swap procedure.  I only have one drive in my main array that was not shucked from a BestBuy Easystore enclosure.  In my backup server, 3 of the 5 drives are shucked.

 

External enclosures are much cheaper than the equivalent bare drives for some reason.

 

All of my shucked drives are WD Red or White drives and they are all Helium CMR drives.  They are either EFZX (Red) or EMAZ (white label) drives. 

 

The Reds are no longer appearing in the external enclosures but the white label drives are the same specs as the Reds or the equivalent HGST helium drives.

 

I have one 8TB drive shucked from an Elements enclosure that I bought directly from the Western Digital store.  I got it on a sale for a mere $115.

 

The BestBuy Easystore 8TB are frequently on sale for $130.  Right now, they are $140.

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Thank you all for those comments.  Thank goodness I asked, as I would have never thought of this.

 

Let me ask this, then.  I currently have dual parity enabled, and I keep a "hot" spare as a cache.  So, that's three 3 TB drives: 2 for parity, one for hot spare.

 

- Should I go back to single parity?  That would allow me to buy two drives, one for (single) parity and one as a hot spare/cache.  My system is really for home use only. 

 

- Does anyone else feel bad paying this much just for parity and spares?  ;-) I'm still using 2TB drives as data drives.  But if I went to 1 parity drive, I could swap two 2 TB drives for two 3 TB drives (the old second parity drive and the current hot spare/cache), and gain 2TB.  And I guess I could add in another data drive too at some point.

 

Thanks again.

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Parity is for primarily for availability rather than protection, if you server fails all data could be lost.

Personally I worry about ~10% of my data, the rest is replaceable. 

 

Multiple parity disks help with large arrays as there is an increased chance of a second failure while performing a rebuild. This is magnified if you have lots of data drives which could be from the same batch etc.

 

You would be better with single parity and a seperate drive(s) (external) to backup critical data rather than dual parity and no backup.

 

Buying the large parity drive can feel like a bitter pill, but once you have it you get full value on any extra disks and as above you reduced the number of spindles.

 

If you got 2-3 8TB drives, you could then replace the smaller drives and use them as backup. 

 

You may also want to reconsider the 'hot spare' as cache. This isn't all that hot as it would need to be cleared before it can be added to the array. I keep a single 8TB drive precleared but spun down so I can add to or replace in the array at any time.... but that's me.

 

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On 8/23/2020 at 5:06 AM, ctviggen said:

Should I go back to single parity?  That would allow me to buy two drives, one for (single) parity and one as a hot spare/cache.  My system is really for home use only. 

Although there is no official statement as to how many data disks one should have in the array before dual parity is a good idea, the generally accepted and promoted idea is eight or more (some say six).  The chances of two disks failing at the same time increases the more disks (parity and array) you have.  The chance that more than one disk is going to fail at the same time with fewer than eight data disks is relatively small and most are willing to run that risk with fewer than eight data drives.

 

This, of course, depends on your risk tolerance.  The recommendation to replace a larger number of small capacity disks with a lesser number of higher capacity disks is a way of reducing potential points of failure.  I would much rather have three 8TB disks in my array than eight 3TB disks, for example.

 

I always have a spare pre-cleared disk equal in size to my largest capacity data disk ready to go in case of a disk failure.  So far, I have not needed to use it.

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  • 1 month later...

Thanks, all.  That's a lot to consider.

 

I have two 3TB parity drives, and 6 data drives (3 3TB and 3 2TB).  I have one "hot spare" 3TB cache drive. I use two 8TB backups from Costco to backup the "real" data on my array (have a lot of recorded TV I don't back up), and store one hidden at home and another at work.  I back the important stuff up at least once a week at home and less for the office version.

 

I like the idea of having a spare that's sitting ready to go.

 

The Costco drives are "real" (normal-size) drives in a case, but I can't see any screws or other way to take them apart to get the real drive out.  I'll work on that, as they have 8TB versions for $130, and I seem to remember they offer these cheaper at times.  I think I bought my backup drives near Black Friday, and they were cheaper than $130.

 

Is it possible to go "backwards" in drives?  That is, if I move to 8TB parity, could I install an 8TB data drive and remove a 2TB drive?  In other words, replace one 2TB drive with an 8TB drive, but (after that process is complete) then remove another of the 2TB drives? 

 

I assume going to a smaller array would also save some power?

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3 hours ago, ctviggen said:

replace one 2TB drive with an 8TB drive, but (after that process is complete) then remove another of the 2TB drives? 

 

I assume going to a smaller array would also save some power?

Any drive that is removed without being replaced and rebuilt will lose the data that's on it. So, no not automatically. You could definitely copy the data from the 2TB to free space elsewhere on the array using any one of many available tools, and then rebuild parity without that drive.

 

The number of drives spinning is a big factor in power consumption, so yes, fewer platters rotating = power saved.

 

3 hours ago, ctviggen said:

The Costco drives are "real" (normal-size) drives in a case, but I can't see any screws or other way to take them apart to get the real drive out. 

AFAIK costco doesn't private label drives, so I'm sure if you search for the brand, model number, disassembly instructions you will find an example on youtube.

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11 hours ago, ctviggen said:

I have one "hot spare" 3TB cache drive.

The idea of using cache as a hot spare doesn't make as much sense as it did back in the pre V6 days of Unraid. Many will have SSD cache now, and cache is used for much more than just caching user share writes, such as fast data for dockers / VMs.

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  • 1 month later...

Sorry, I have too much to do.  I'm currently adding 2 inches of rigid foam to the concrete walls of my basement, and that is taking every waking moment on the weekends. I'm getting a respite this weekend (Thanksgiving).  Thus, I'm returning to this topic.

 

An update.  I'll likely go get three drives from Costco.  They are "Seagate backup plus hub", 8TB drives.  I did find a few teardowns of these.  Apparently, they use plastic clips and you destroy some of them when removing the drive.  But I guess that's not a big deal, since you want the drive anyway.

 

My goal then will be to move from my current configuration:

 

Two 3TB parity drives;

6 data drives (three each 3TB and 2TB) (15TB data); and

One 3TB cache.

 

To:

 

One 8TB parity drive;

Two 8TB drives for data (16 TB data);

? for cache. 

 

I obviously have not been keeping up here, because the last time I remember, SSD drives were overkill for the cache.  It's interesting to see them moved to being used for the cache.  That's too bad, as I just gave away a 120 GB SSD, which I wasn't using.  I may look for an SSD on Black Friday.  Any size that I should look for?

 

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2 minutes ago, trurl said:

Depends on how you will use it and/or how much you want to spend. And with nvme in the mix now, what your hardware will support.

Thank you.  My hardware is old -- as in I don't remember when I bought it old.  In the time my unraid server has been running (24/7/365, except for power outages), I've gone through at least 3 home theater computers (which also run 24/7/365 when they work).  Each one has failed. And I've only replaced a few drives (2?) this entire time in my unraid server.  (Maybe I should knock on wood or do whatever I have to do to not jinx this!)

 

Because of the age of the hardware, I was thinking of buying new hardware just to have it.  Not sure I can buy 3 new drives AND new hardware, though, at least at this time.  

 

Right now, my unraid server is "just" a NAS device.  In the short-term, my basement project is taking so long, and I have at least 5-6 more weekends of work (at least - hard to tell, always much more time-consuming than I think it will). Once the project is done, maybe then I could devote more time to see what I can do with unraid. 

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I do.  I then have the cache sent to the array on a relatively short interval (every hour?). (I lost data, so I shortened the interval. I subsequently traced this to a crappy SATA board, and I bought one recommended on here and haven't had an issue since. I forgot and haven't changed the writing interval.)

 

So, the only thing I currently do with the cache is cache the user share writes.

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Mover is intended for idle time. If you don't cache much and it is idle that often then that is fine. If it isn't idle that often then it probably makes more sense to just write directly to the array.

 

Cache is also often where dockers and VMs are stored, so their performance won't be impacted by slower parity, and so they won't keep array drives spunup.

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Thanks again.  I do think it's idle a lot.  We do, however, record TV on it, but (assuming I'm not home, as I am today) it should be idle a ton during the day.  Not too many shows during the day.

 

I have two dockers, one for TV, and one I don't really use.  I think they are both on the cache, but will have to check. 

 

Thanks again for your help.

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