gtaus

I just removed the letters on all 8 pool drives and nothing exploded!
Same for SB scanner, business as usual (except for now blank drive letters
 
You now have me interested in leaving them unlettered, but there must be a scenario/usage case where lettered pool drives are desirable.
EDIT:
Should a need arise, I could always revert to letters, but I'll leave them out for now and see how it goes.
Thanks @gtaus

Yeah, old habits... When I removed the drive letters and just used drive names, life with DrivePool became easier with my 16 HDDs. It works better for me.

This sounds like good news to me
I think when I started using drivepool, individual drives were "letter-less" (file explorer would only show pool drives, and non-pooled OS drive also, obviously)..
For a specific reason I fail to remember (lets call it old habits), I switched to lettering and never looked back once.
Thanks !

Hi gtaus, I can see that your account is following this thread, so hopefully you'll get notified about this response.
Maybe check that https://community.covecube.com/index.php?/notifications/options/ is set to your liking?

Checking, it seems the ST6000DM003 is a SMR drive. I don't recommend putting it in any pool where you want decent rewrite performance, but if you're only wanting good read performance it's fine.

... Would that 6TB USB HDD happen to be a Seagate Backup Plus Hub by any chance?
Because I bought one a ways back (P/N 1XAAP2-501) and it behaves exactly the same way you've described. The drive inside might actually be okay, just with a lemon enclosure. Since yours is out of warranty and you're planning to ditch it, consider instead shucking it and using the HDD as an internal drive (run the Seagate long test on it again of course).
BTW just FYI, Seagate has used SMR drives in its Backup Plus Hubs and I don't recommend using SMR drives in a pool, so also check the part number of the drive itself to see if it is one, with (if you don't want to open it up to check) a utility like Crystal Disk Info or similar.

I think a 2nd Pool for non-critical data using old hardware is an excellent idea.

Well, my excellent idea has proven successful, but maybe in an unexpected way. I created a 2nd DrivePool for my non-critical \movie\ data using my suspect 6TB USB HDD. Everything seemed to be working fine as I used Teracopy to move 6TB of \movie\ files to the new DrivePool using the verify command to ensure all files were 100% correct upon transfer. Everything worked fine for a day or two. Thinking I was good to go, I was about to add some more older HDDs to that 2nd DrivePool when, for whatever reason, that 2nd DrivePool went offline and I could not access it (only the suspect 6TB USB HDD on the pool at that time). Fortunately for me, I only had that one suspect 6TB HDD on the 2nd DrivePool at that time, so troubleshooting was fast and easy. Turns out, that suspect 6TB HDD has a tendency to shut itself down, go offline, and then throw the DrivePool into an error state. I was able to unplug the 6TB, plug it back in, and then both the drive and the 2nd DrivePool came back to life.
This happened a couple more times yesterday, with that 6TB USB HDD going offline seemingly random, requiring me to unplug it and then plug it back in, so I decided it was just not worth the trouble trying to salvage use out of that 6TB HDD anymore. I am currently in the process of using Teracopy with verify to move all the \movies\ file off that 2nd DrivePool with only the 6TB USB HDD back to my original DrivePool. 
Turns out that creating a 2nd DrivePool using only that suspect 6TB USB HDD was a good idea because I quickly was able to determine there is indeed something wrong with it (despite all the diagnostic programs that scan it and report it is working fine). The only program that correctly determined the HDD was failing was Seagate Seatools using the long generic test (it passed the short tests). Unfortunately, the HDD is out of warranty so I will have to just eat the loss and move on.
But, I would like to shout out to Stablebit Drivepool because, even though that 6TB HDD is failing, my data seems to be recoverable. I am currently about 50% complete on the file transfer off that suspect HDD and all files are intact. I can guarantee you that if that same suspect HDD had gone bad in my MS Windows 10 Storage Spaces setup, using data packets spread all over the pool, it would have most assuredly crashed the entire Storage Space and all my data would have been lost. How do I know that? Because I used Storage Spaces for years and after my 3rd catastrophic loss of data due to a HDD failure, I moved over to Storage Spaces. Despite having 2 and even 3 HDD failure protection on Storage Spaces, I lost entire pools of data when only 1 drive out 20 drives went bad. I guess I can attest to the fact that when a HDD goes bad in DrivePool, I have been able to recover my data off that failing HDD. For my few folder/files that require duplication, I have 2x or 3x duplication set and with DrivePool I don't worry that any 1 drive will crash my entire pool.
Thanks to everyone for their responses and helping me work through this issue.

I have never tried to use File Placement Rules but as I understand it, if you tell DP to place \movies on that 6TB HDD then it will and also spill over to other drives when the 6TB HDD is full. DP will not, I think, through a no space error. Not sure how to ensure that non other data arrives on that drive, that might need a lot of FPRs, but may be easy.
Having said that, I would not add a drive I am suspicious about if, unlike me, you do not use duplication. Do you have Scanner? Maybe run the Seagate tool again.

another way would be if you dont need duplication
1 dont add the disk to the pool
2 use backup software - set a job to copy the changed/added files to it - nightly job or similar
simpler and you dont have to mess with FPR's that may get complex
also you can detach it and move it to another pc without having to remove it from DP as it would throw an error

In the File Placement Rules section:
your FIRST (uppermost) rule should be that all files matching "\movies\*" are to be placed on all drives INCLUDING that one (check all drives) your LAST (lowermost) rule should be that all files matching "*" are to be placed on all drives EXCLUDING that one (check all the others, leave it unticked, and in your particular case you also want to select "Never allow files to be placed on any other disks" for this rule). Any other rules you might have should be placed ABOVE the LAST rule, and should not have that drive checked (and again, you may wish to select "Never allow..."). This is because FPR checks the rules from uppermost to lowermost until it finds a matching rule for the file being balanced and then uses only that rule.
NOTE that File Placement is only performed when balancing is triggered instead of in real time; you might wish to use the SSD Optimizer balancer plugin to mark at least one of the other disks as "SSD" so that new files are never even temporarily placed on the 6TB HDD, which is otherwise possible even if you have "Balance immediately" selected in the Settings tab.

For whatever it's worth, in the past I have encountered problems with "copier" software silently missing files. Admittedly I was dealing with very large file sets, very long paths, and unicode names, all back when a lot of software would have trouble with just one of those let alone all three, and the less-than-reliable hardware I was (ahem) relying on at the time probably didn't help, but the important takeaway is that if you're working with "irreplaceable" data you might want to stress-test your copier and verify that it is actually doing what it says it's doing.

I have only been using DrivePool for a short period, but if I understand your situation, you should be able to open the DrivePool UI and click on the "Remove" drive for the drives you no longer want in the pool. I have done this in DrivePool and it did a good job in transferring the files from the "remove" drive to the other pool drives. However, given nowadays we have large HDDs in our pools, the process takes a long time. Patience is a virtue.
Another option is to simply view the hidden files on those HDDs you no long want to keep in DrivePool, and then copy them all over to the one drive you want to consolidate all your information. Once you verify all your files have been successfully reassembled on that one drive, you could go back and format those other drives. The main advantage I see with using DrivePool is that the files are written to the HDD as standard NTFS files, and if you decided to leave the DrivePool environment, all those files are still accessible by simply viewing the hidden directory.
I am coming from the Windows Storage Space system where bits and pieces of files are written to the HDDs in the pool. When things go bad with Storage Spaces, there is no way to reassemble the broken files spread across a number of HDDs. At least with DrivePool, the entire file is written to a HDD as a standard file, so in theory you should be able to copy those files from the pool HDDs over to one HDD and have a complete directory. I used the Duplication feature of DrivePool for important directories.
Again, I am still learning the benefits of DrivePool over Storage Spaces, but so far, I think DrivePool has the advantage of recovering data from a catastrophic failure whereas I lost all my data in Storage Spaces. If there is a better to transfer your DrivePool files to 1 HDD, I would like to know for my benefit as well.

I have only been using DrivePool for a short period, but if I understand your situation, you should be able to open the DrivePool UI and click on the "Remove" drive for the drives you no longer want in the pool. I have done this in DrivePool and it did a good job in transferring the files from the "remove" drive to the other pool drives. However, given nowadays we have large HDDs in our pools, the process takes a long time. Patience is a virtue.
Another option is to simply view the hidden files on those HDDs you no long want to keep in DrivePool, and then copy them all over to the one drive you want to consolidate all your information. Once you verify all your files have been successfully reassembled on that one drive, you could go back and format those other drives. The main advantage I see with using DrivePool is that the files are written to the HDD as standard NTFS files, and if you decided to leave the DrivePool environment, all those files are still accessible by simply viewing the hidden directory.
I am coming from the Windows Storage Space system where bits and pieces of files are written to the HDDs in the pool. When things go bad with Storage Spaces, there is no way to reassemble the broken files spread across a number of HDDs. At least with DrivePool, the entire file is written to a HDD as a standard file, so in theory you should be able to copy those files from the pool HDDs over to one HDD and have a complete directory. I used the Duplication feature of DrivePool for important directories.
Again, I am still learning the benefits of DrivePool over Storage Spaces, but so far, I think DrivePool has the advantage of recovering data from a catastrophic failure whereas I lost all my data in Storage Spaces. If there is a better to transfer your DrivePool files to 1 HDD, I would like to know for my benefit as well.

Thanks for the response. Turns out, I was clicking on the down arrow and that did not give the option of enable auto scanning. So after reading your response, I clicked on the "button" itself and it toggled to enabled. Problem solved. Auto scanning immediately started so I know that it is working. Thanks.