Jaga

I haven't messed with the server implementation of ReFS, though I assumed it used the same core.  I ditched it ~2 years ago after having some issues working on the drives with utilities.  Just wasn't worth the headache.  I never had actual problems with data on the volume, but just felt unsafe being that "out there" without utilities I normally relied on.  When the utilities catch back up, I'd say it's probably safe to go with it, for a home enthusiast.  Just my .02 - I'm not a ReFS expert.
Shucking has positives and negatives, to be sure.  There's one 8TB drive widely available in the US that normally retails for $300, and is on sale regularly for $169.  For a reduction in warranty (knowing it's the same exact hardware in the case), I'm more than happy to save 44% per drive if all I need to do is shuck it.  They usually die at the beginning or end of their lifespan anyway, so you know fairly early on if it's going to have issues.  That's my plan for the new array this July/Aug - shuck 6-10 drives and put them through their paces early, in case any are weak.
 
No need to RAID them just for SnapRAID's parity.  It fully supports split parity across smaller drives - you can have a single "parity set" on multiple drives.  You just have to configure it using commas in the parity list in the config.  There's documentation showing how to do it.  I am also doing that with my old 4TB WD Reds when I add new 8TB data drives.  I'll split parity across 2 Reds, so that my 4 total Reds cover the necessary 2 parity "drives".  It'll save me having to fork out for another 2 8TB's, which is great.

Thanks for all the awesome input everyone. 
I think I'm gonna say with NTFS. Especially as the SnapRaid site seemingly throws up some suggestions linking to this article https://en.wikipedia.org/wiki/Comparison_of_file_verification_software 
With regards to Shucking... Although as mentioned I have done this is the past (with 4TB drives when 4TB was the latest thing) the cost difference is negligible especially bearing in mind  the reasons Christopher mentions and not an approach I want to return to. Though the cost isn't really the issue my current aim is to get rid of/repurpose some of those 4TB drives and replace them with another couple of 8TB drives. Maybe when that's done I will look again at SnapRaid and It's parity. If Google ever backtrack on unlimited storage at a stupidly low price in the same way Amazon did then it may scale higher on my priorities, but for now... 
 
EDIT
Now I'm even more curious as I have just read a post on /r/snapraid suggesting that its possible to raid 0 a couple of pairs of 4TB drives and use them as 8TB parity drives. Though the parity would possibly less stable it would give me parity (even though it's not priority) and would allow for data scrubbing (my main aim) and mean that those 4TB drives wouldn't sit in a drawer gathering dust. So if any of you Snapraid users have any thoughts on this, I would be glad for any feedback/input.. 
 
 
 

Honestly, I'd say use NTFS.  
In Server 2012R2, and up, I'd say it's pretty much ready. 
The biggest issue is that most disk tools are NOT compatible with ReFS yet. Which is the real problem. 
As for bit rot, that's a fun subject.
That saves you cost up front, and dumps the cost on the warranty. Eg, you have none. So if the drive fails, you may be SOL, if you didn't save the enclosures. 
But seriously, a 3-5 year warranty is worth the difference, IMO. 
Actually it does.  It's not the same effect, but the outcome is the same:  bleeding.   It's part of why there are a limited number of writes, IIRC. 
 

Thank you Chris and Jaga. Ended up just copying everything over so that everything would be in 1 pool. Forced me to do some much needed digital housekeeping.

Yup, what Jaga said.
Specifically, the software doesn't automatically rebalance the data like this, unless there is a specific reason to do so (such one or more disks being too full).
Over time, it will accomplish a balanced layout, because new files are added to the disk with the most available free space. 
However, as Jaga indicated, the "Disk Space Equalizer" balancer plugin aggressively rebalances the pool, so that each disk has the same percentage used, or the same amount of free space (your choice).

You'll want to get the "Disk Space Equalizer" plugin for DrivePool from this page, and enable it to force an immediate re-balance.  When it's done, turn it off again and let DrivePool do automatic balancing from then on.

Hello everyone:
Not sure if this is the correct Forum for this, but I just wanted to let you all know about what I consider to be a fantastic deal on some 4TB Drives at Newegg.  Drashna, you can move it if you need to. To save everyone’s time, I’ll just give you the stats:
·       Brand:                      Toshiba
·       Model:                      MD04ACA400 (Bare Drive)
·       Capacity:                 4TB
·       Size:                         3.5”
·       Speed:                     7200RPM
·       Connection:            SATA 6.0Gb/s
·       Cache:                     128MB
·       Warranty:                5-Years from Toshiba
·       Seller:                      Newegg
·       Item Number:        N82E16822149644  (Newegg)    
·       Shipping:                Free, 3-Day Fed-Ex  
·       Price:                      $93.49  (That’s $23.37 per TB, Delivered!)
IMPORTANT: When you do a Search for the drive on Newegg’s site, do so using only the Newegg Item Number. The drive does not come up with an ordinary search, but the same model from GoHardDrive.com DOES come up for $93.00 or so with a 3-year warranty. If you want, you can just try this direct link to the Newegg offering:
https://www.newegg.com/Product/Product.aspx?Item=N82E16822149644       Newegg says they are discounting the drive from $205.99 (55%).
I found the Newegg offering quite by chance after I had to return BOTH the drives I purchased from GoHardDrive.com due to numerous bad sectors right out of the package. ALSO, the GoHardDrive units have Manufacturing dates 18-24 Months ago and GoHardDrive is providing the warranty themselves. The Newegg drives I purchased were made in Feb, 2018. I just finished running them through extensive testing and they are both in Perfect 100% Health with no errors at all. I have verified the 5-Year warranty by Serial Number directly on Toshiba’s website. Here’s the link for that (not easy to find):
https://myapps.taec.toshiba.com/myapps/admin/jsp/webrma/addRequest1NoLogin.jsp?Action=NEW
These seem to be good quality drives. When I bought them, Newegg was advertising them as Enterprise Drives. I already knew they weren’t however and I bought them anyway. 5-Years is a SUPERB Warranty! Now in the new listing, they dropped “Enterprise” and just say “Good for Servers”.
Hope I’m not wasting your time. I did do a search on the Forum to make sure no one had already said something and I didn’t see anything.
If you’re interested, don’t dally on it. Enough people already do know about them that they are selling like crazy. Newegg told me they are already on their second order of 10,000 drives!
Hope this helps someone,
GDog

Very nice!

I recently found out these two products were compatible, so I wanted to check performance characteristics of a pool with a cache assigned to it's underlying drives.  Pleasantly, I found there was a huge increase in pool drive throughput using Primocache and a good sized Level-1 RAM cache.
This pool uses a simple configuration: 3 WD 4TB Reds with 64KB block size (both volume and DrivePool).  Here are the raw tests on the Drivepool volume, without any caching going on yet:

 
After configuring and enabling a sizable Level-1 read/write cache in Primocache on the actual drives (Z: Y: and X:), I re-ran the test on the DrivePool volume and got these results:

 
As you can see, not only do both pieces of software work well with each other, the speed increase on all DrivePool operations (the D: in the benchmarks was my DrivePool letter) was vastly greater.  For anyone looking to speed up their pool, Primocache is a viable and effective means of doing so.  It would even work well with the SSD Cache feature in DrivePool - simply cache the SSD with Primocache, and boost read (and write if you use a UPS) speeds.  Network speeds are of course, still limited by bandwidth, but any local pool operations will run much, much faster.
I can also verify this setup works well with SnapRAID, especially if you also cache the Parity drive(s).
I honestly wasn't certain if this was going to work when I started thinking about it, but I'm very pleased with the results.  If anyone else would like to give it a spin, Primocache has a 60-day trial on their software.

A -  Yes, it is - any OS that can read the file system you formatted the drive with (assuming NTFS in this case) can see all it's files.  The files are under a "poolpart..." hidden folder on each drive, fully readable by Windows.
B -  Yes, it will work with Bitlocker.  This is a quote directly from Christopher on these forums:  "You cannot encrypt the DrivePool drive, but you CAN encrypt the disks in the pool."  (Link)

They stay on the disk, outside of the pool, and are considered "other" data.  And nothing will be in the pool.
You want this: 
http://wiki.covecube.com/StableBit_DrivePool_Q4142489
 
As for the existing drive letters, you may want to take a look at this: 
http://wiki.covecube.com/StableBit_DrivePool_Q4822624

Editing my post for a bit more clarity:
You can use duplication and then simply take the drive out of the machine, and revert duplication to x1.  However according to the DrivePool feature list, when you remove a disk from the pool via the software options:
Provided you have enough available space on other disks in the pool, then Christopher is correct in that a removal will transfer all files to other disks prior to removing the drive you wanted.
I'm not sure which option is faster.  Either should work.  Christopher's advice is probably the best you're going to get.

Sounds like something is reading data on the pool, and keeping the drives active. 
Just in case, try disabling "BitLocker_PoolPartUnlockDetect", by setting the "override" value to "false" and rebooting:
http://wiki.covecube.com/StableBit_DrivePool_2.x_Advanced_Settings#Settings.json

That did the trick! Thanks much for this! My array now spins down like it's supposed to do. Was this a new default setting as of the last update?

Ask someone what the term "spinning rust" means in 20 years and they may look at you funny.   
Let us know how it goes WickedLlama!

Well, the big part is writing here.  That triggers ECC and reallocation in the drive's firmware.  
If that doesn't work, a full format "may".  But if that doesn't work, RMA time. 
By retire, ... well, I have a nice pile of rare earth magnets. 

Good to know, learn something new every day!
 
Now that is an awesome idea.

Not quite.  It's essentially a reverse proxy for the file system.  The commands and processed and forwarded to the underlying drives. 
My (100% blind) guess here is that Oculus is using hardlinks.  That would definitely error out, as we do not support those on the pool. 
But if you could, enable tracing, and reproduce:
http://wiki.covecube.com/StableBit_DrivePool_2.x_Log_Collection
 
Also, if you want a super hacky hack.... install it to "x:\poolpart.xxxxx\Oculus", and then run from the pool.

If the sector has no data in it currently, a secure erase of all empty sectors on the drive would work.  Some tools available to do that can be found here:  https://www.raymond.cc/blog/make-your-recoverable-datas-unrecoverable/
If it has data in it, simply finding the file via a block map tool and deleting it (removing it from the MFT) would mark the sector empty, allowing you to then do a secure erase which would force a write to it.

Are your parity drives the same make/model as your data drives?  Some firmware features aggressively attempt to spin down drives (park heads/sleep) while some are more relaxed.  I had to patch my WD Reds since they were parking heads after just 8 seconds of inactivity, raising the load cycle count unnaturally in a NAS.

Nope.  Just our drivers.  That way, we can see if/where the issues are occurring in relation to our code. 
Thanks.  Though. I'm not sure which it is.  If you could, open a ticket at https://stablebit.com/contact and mention this ticket.
Correct.  And that's the point here, actually.  The verifier may/will cause it to crash in a different way, because of how it works. 
And looking at the crash type, it's directly related.  The "Pool" part in both types refers to the system memory ("memory pool"), so this does appear to be related. 
 
Oh boy.  That's not good.  And I've flagged that info for Alex, just in case it's helpful.

Just noticed this alert on another piece of software when it updated.  Sounds like it could be related to the issues people are seeing in this topic.
 

Unless you're seeing actual corruption, this may be due to "IO" issues. Eg, data not downloading fast enough. 
And if this happened around the time that you created a new drive, then this most likely a timing issue, where the drive was created but not fully usable yet. 
 

Done.  Seems to have worked.  After installing that version of Scanner, I am no longer getting File System Damage warnings on all the drives in my pool.  
Though I'm not certain these were all "false positives".  Throughout my many rounds of testing the drives, CHKDSK /F  had reported what appeared to be legitimate MFT Mirror Corruption and/or Bitmap Errors.  But those have likely been resolved/repaired, and no new warnings have been triggered.  So I think (hope) I'm good.  
I am now in possession of 5 new Seagate 8TB External USB 3 drives.  My plan was to shuck those, and install the drives in some sort of external enclosure.  I prefer to avoid USB 3, and I've had plenty of issues with eSATA in the past.  My server mobo has USB 3.1 Gen 2 ports (10Gbps) on it (1 Type A and 1 Type C).  I see that there are a few enclosures with USB 3.1 Gen 2 connections.  The speed of USB 3.1 Gen 2 is appealing, but would it also be prone to the same kinds of disconnection issues as USB 3.0/3.1 Gen 1?
Next month, I will get two more 8TB internal (NAS) HDD's, which will finally allow me to turn on duplication on my entire pool.  This has been a process, but progress is being made.
Thanks for all the help!
 

Its now showing 1.22 mb of damaged but i see no red sectors...i will just treat this usb key as suspect...no more time should be wasted on it