gtaus

There isn't a set amount of time, because tasks like balancing, duplication, etc run as a background priority.   This means that normal usage will trump these tasks.   
Additionally, it has the normal file move/copy issue, estimates can jump radically.   A bunch of small files take a lot more time than a few large files, because it's updating the file system much more frequently.  And for hard drives, this means that the read/write heads are jumping back and forth, frequently.  
But 6-12 hours per TB is a decent estimate for removal. 

Likely very little difference versus plugged directly into the motherboard.
It is possible to evacuate/move files much faster if you don't mind stopping the DrivePool service while you manually move them yourself (from hidden poolpart to hidden poolpart) then restarting the service and requesting a re-measure. Basically a tradeoff between speed and comfort, if that makes sense.

Yes, DrivePool, like many of my Windows programs, sometimes hangs and requires a reboot. Most of the time DrivePool works without any problems, but I have run into some circumstances where DrivePool misbehaves and does not correct itself until after a reboot.
I ran Windows Storage Spaces for ~7 years, and the small problems I occasionally experience with DrivePool are nothing compared to the problems I had with Storage Spaces trying to manage the same size pool (currently 70TB).
IF I had any real complaint about DrivePool, it would be that it really keeps you in the dark on background tasks it performs. I personally would like more status info displayed in the DrviePool GUI in those cases, because background tasks might have a really low priority and it may look like nothing is happening. Well, it may be happening but not very fast. Or, maybe the task got hung up and needs a reboot. Sometimes you can go into Task Manager and check for disk activity there. I have done that on occasion to verify activity was really going on in the background tasks. It would be nice to have the option of seeing some of that background activity on the DrivePool GUI. Most of the time I don't care as long as it gets done. Sometimes I want to verify work is actually going on.
FWIW, I had the same idea as you when I was testing out DrivePool. I did a couple disk removals, but they worked just fine on my system, so I started off with a positive experience.

I understand what you want to do, but I don't have the answer with my limited knowledge using home based meida servers. What OS are you running? There may be some solution in higher priced enterprise based servers, but I would not know how to do it with DrivePool. I know DrivePool can work with sub-pools, but I think they have to be on the same server. Maybe not. I hope somebody can give you more direction.
BTW, a 45 drive case?! I would be interested in what you use. I currently have 19 USB HDDs (80+ TBs) on my DrivePool, but I have problems loading all those drives on a reboot. I had to buy USB power hubs that have individual on/off switches for each port. When I reboot my server, I first have to turn off all my USB drives, then when the server is up and running, I have to turn on each drive, one by one, waiting maybe 30 seconds for each USB drive to be recognized by the OS before I go on to the next drive. If I could dump all those HDDs into one case and bypass my current USB problems, that would be great. If you can, let me know what you use so I can check it out.

I don't use the File Order Placement on my DrivePool, but as I understand it, you can order your drives in the priority they should be used. If you designated your 12TB Seagate Exos as the last drive to be used in the pool, that should significantly reduce the writes to that drive as long as your other drives with higher priority have free space. At the same time, you could also manually transfer files to/from your 12TB Seagate drive when you want. If you have files on the 12TB Seagate that you constantly need to read, then I would manually move them to another drive.
If you have lots of frequently used files to move off the 12TB Seagate, then you might consider to "Remove" the drive from DrivePool, have DrivePool empty its data from your 12TB drive, and then add the 12TB Seagate back in again to the pool as the lowest priority drive in the pool. Then you could manually move rarely used files to the empty 12TB Seagate and basically have the 12TB drive there as storage. I think that would work. I'll be reading this thread to see if there are other ideas.

GoHardDrive support is top-notch.  I have used their warranty policy, and they stand behind it 100%.  As long as you have the serial number, they will replace a failed/failing drive.

Just a quick follow up. I mounted all my DrivePool drives into a mount folder as you suggested, and it did indeed solve the issue of being able to catalog each drive. I had been trying to figure out a solution to that problem for a couple of years, and your method is easy to implement, and it works. Thank you very much for that suggestion.

Instead of assigning drive letters to your 20 USB disks, you could mount them in a folder. This means that the disks can be accessed individually at any time to catalogue or check their content, but they don't clutter up Windows File Explorer (since they appear as  subfolders of the C: drive). You can also CHKDSK the individual disks if needed. I have set up my drive pool in this way, although I have only 4 USB disks in the pool:
C:\Mount\Pool_1 C:\Mount\Pool_2 C:\Mount\Pool_3 C:\Mount\Pool_4 You specify the mount point on the Windows panel where you assign drive letters.
-- from CyberSimian in the UK

It's terrible to lose data. Having said that, I don't follow what your situation is. I have never had any data lost from adding a HDD to DrivePool. 
Is it your Drive D that you believe was formatted? That's the only drive that appears to have no data.
On the top left corner of the Pie Chart DrivePool main page, you have 3 messages logged. You might want to click on that small pie chart and read what DrivePool has logged. Sometimes that gives you clues.
Is there a reason you added your Drive C to your DrivePool? I know it's possible to add Drive C to DrivePool, but I personally never use my Drive C for any pools. I try to keep that Drive C from outside storage programs.
As far as trusting DrivePool, well, it works better for me than my old hardware RAID setups, or when I used Windows Storage Spaces. I had massive data loses with a single HDD failure in both those other systems. In fact, even though I had triple redundancy on my Windows Storage Spaces, I had a single HDD failure and it destroyed my entire Storage Space volume. That was not supposed to happen.
I switched over to DrivePool a couple years ago. I have had HDD failures using DrivePool, but it only affects the data on the failed HDD. Many times, I was able to physically remove the drive, plug it into a desktop caddy, and transfer almost all the data off that failing HDD. 
DrivePool is not a backup plan, but you can turn on duplication for the entire pool, or specific folders. In theory, that should allow you to rebuild your data faster when you add a new drive to the pool after a HDD failure. I find that useful for some data. Mostly, my DrivePool is used as my Home Media Server and I have all my data backed up on HDDs sitting in my closet. I mostly trust DrivePool to handle my server data, but like anything with computers, you really need to have a good backup plan to ensure no data loss if you have HDD failures. After running DrivePool for a couple of years, I only have single copies of media data on my DrivePool Home Media Server. If I lose a pool HDD, then I'll rebuild from my backup HDDs if still needed. 

Whenever I have problems with duplication, I go to the Settings Cog>Troubleshooting>Recheck Duplication and let DrivePool try to figure it out. Honestly, if there are duplication problems with DrivePool (like after removal of a failed HDD), it takes me a couple times running the Recheck Duplication and Balancing tasks. Last time that happened to me, it literally took a few days for DrivePool to clean itself up, but I have 80TB in my DrivePool. To be fair to DrivePool, it did fix itself given time.
I only have a few folders set for duplication in my DrivePool, so out of my 80TB pool, only about 20TB are duplicated. Also, DrivePool duplication is good for some things, but it does not ensure that your files are actually intact and complete. It is possible to have a corrupted file/folder and DrivePool is happy to duplicate the corruption. If there is a mismatch between the original and the copy, DrivePool cannot tell you which file/folder is true and which may have been corrupted.
For example, my DrivePool is mainly used as my home media storage. If I have an album folder with 15 tracks, and one or two tracks gets deleted or corrupted, DrivePool cannot tell me if the original directory is complete, if the duplicate directory is complete, or if neither copy is complete. Because of this, I now add 10% .par2 files to my folders for verification and possible rebuild. With the .par2 files, I can quickly determine if the folder is complete, if any missing or corrupted files can be rebuilt from the .par2 files in that folder, or if I have to take out my backup HDDs from the closet to rebuild the corrupted data in DrivePool.
Unfortunately, DrivePool duplication does not ensure that your data has not been corrupted. For this reason, I don't consider DrivePool duplication in any way a backup solution. It lacks the ability to verify if the original or the duplicate copy is complete and intact and cannot resolve mismatches between copies. In theory, from what I understand, duplication is mainly good for rebuilding your DrivePool if you have a HDD failure and the bad drive is a complete loss. Then, DrivePool will still have a copy of the files on other drives in DrivePool and can rebuild the failed data. That may be a great option, and of course I said I do use duplication, but DrivePool duplication still lacks any ability to verify if the files are complete and uncorrupted. For that reason, I have gone to using those .par2 files for file verification. My backup HDDs are stored in my closet.
It's not the best solution to my backup needs, but it is the best I have found for me at this point. In a more perfect world, DrivePool would have the ability to duplicate folders for faster pool recovery, and there would also be some way to verify and rebuild lost data like the .par2 files. In your case, if you have good backups of your data, I might consider turning off duplication in DrivePool, Rebalancing the pool and/or forcing a Recheck Duplication to clean up the data, and then turning duplication back on for the folders/pool as you want. But before I did that, I think I would contact the programmer directly for support and ask him for his recommendation(s).
DrivePool is a great program and data recovery is much better than other methods I have used such as RAID systems and Windows Storage Spaces. But I do run into errors like you are experiencing and I cannot always understand the corrective action to take. Mostly, I have found that DrivePool is able to correct itself with its various troubleshooting tasks, but it might take a long time on a large pool.

I don't think the SSD Optimizer works that way. When it hits the trigger point and flushes data, it appears to flush all the data in the cache. There is nothing left in the cache after the flush. 
I think there are some SSDs with learning software that will keep your most used programs/data on the SSD. Those are typically system SSDs. The DrivePool SSD Optimizer is not designed for keeping your most used files on the SSD. However, DrivePool can use your SSD as both a pool drive and a system drive. You could simply install the programs and/or put those files you use most often directly on the SSD and not as part of DrivePool.
For example, my DrivePool SSD is drive Z:. I can install, store, or locate any files I want on my Z: drive as normal, or I can also use that SSD in DrivePool which adds the hidden DrivePool PoolPart directory on my Z: drive.
One of the big advantages to DrivePool over other systems such as RAID or Windows Storage Spaces is that you are able to add and use an existing drive to DrivePool and, at the same time, also use that drive normally on your system. My older RAID and Storage Spaces took full control over my drives and those pool drives could not be used for anything else.

I used to run a Windows Storage Spaces server for about 7 years. The last 2 years, as my pool kept larger and larger, I had more and more problems with Storage Spaces. I spent a long time considering other options including FreeNAS. I talked to people who were running, or used to use, FreeNAS and learned that FreeNAS has problems like Storage Spaces when the pool gets large.
At that time, I was just over 80TB on the pool and having significant problems with Storage Spaces that I did not have when the pool was much smaller. The people I talked to about FreeNAS told me similar stories, it worked fine to a point and then when the pool got larger, they started having significant problems. In fact, the guys I talked to had already given up on FreeNAS and moved on to other options.
I moved on to DrivePool and my experience has been much better. I am now over 80TB on my DrivePool server and, so far, have not seen the problems I experienced with Storage Spaces. There are some things I miss about the "promise" of Storage Spaces, but in real life, the performance of Storage Spaces falls short. My friends running FreeNAS told me the same story with using FreeNAS.
I am not claiming that DrivePool is perfect, but it just seems to work better for me. After adding a SSD to DrivePool as a front end cache, I now get write speeds that exceeded my Storage Spaces setup. If you chose to duplicate some folders in DrivePool, then you have the option of using Read Striping and that can almost double your read speed in some scenarios.
However, I chose DrivePool over other options not because it was faster, but rather because it just worked better for me. When a pool drive fails in DrivePool, you only lose the data on that one drive, not the entire pool (as happened to me in Storage Spaces). If you have duplication set on either the entire pool or just certain folders, you can rebuild the pool from the duplicated data. Also, when I have had HDDs fail, sometimes most of the data on that drive is still available and can be transferred back to the pool. In one instance, I had only 2 or 3 corrupt files on a 3TB HDD that was failing. I was able to move all good files off the drive before it finally, totally, failed.

I tried to buy my Amazon renewed drives from the seller GoHardDrive. I have purchased drives from GoHardDrive for years and their customer support has always been first rate. I feel confident they would back their warranty.

Nicely done. Looks like Stablebit Scanner has more sorting options than Hard Disk Sentinel.

Fortunately, no. I have 18 USB drives and was very happy when I discovered that DrivePool did not require Drive Letters to work. I have auto update on Windows 10, so I imagine I have the latest updates. Everything is working fine here.
Although I do not use Drive Letter assignments, I have all my pool drives named. Since I am so clever, I named them DP01, DP02, DP03, etc... and they sit on a shelf in that order, too. I also labeled the drives with a small tag. Makes it easy for me to pull a drive if it has any problems.
I hope you find out what happened to your DrivePool and why you now need Drive Letters assigned. I'll be reading to see what develops. Hope you get a fix soon.

Welcome to the forum.
As to stealing this topic.... on the top of this thread it states that the issue was solved by @Christopher (Drashna) way back in 2016. Given that DrivePool has been updated many times since then, if you have a similar issue as this old thread, then it might be better to start a new thread with your concerns.
There was just another recent thread on the SSD Optimizer. You might also find that discussion helpful. 
When I was first setting up my SSD cache, I noticed that sometimes it would not flush properly until I rebooted the computer. After making changes to the SSD cache settings, it appeared to hang on the flushing. Through trial and error, I discovered everything with the SSD cache flushing to archive drives worked as expected after a reboot. I have not changed my SSD cache settings for some time now, and it flushes as expected without any problems.
If rebooting your computer after you change your SSD cache settings does not work for you, I'd suggest starting a new thread because this thread is already marked as solved. I think you would get more responses that way. Take care.

The SSD write cache did increase speed on my system, but it depends on my file transfer scenario. If I am transferring files directly from my server's drive into DrivePool on that same server, I see my maximum speed of the SSD (about 480 MB/s). If I am transferring files over my home network ethernet (about 30 MB/s), or wifi (? MB/s), or from an attached USB HDD (about 80 MB/s), then even my DrivePool archive HDDs are fast enough to keep up with the transfer. 
I have set aside 100 GB of my 228 GB SSD as my DrivePool write cache and also use that as a cache for my working temp folders. In that way, the 100 GB SSD cache not only works for DrivePool writes, but also as my system cache for both reads/writes for my temp working folders. In those cases, the SSD cache read/writes at about 480 MB/s whereas just my DrivePool archive HDDs would max out around 80-100 MB/s. So, yes, the SSD can significantly increase your speeds, but it all depends on your specific setup.

DrivePool has a feature called Read Striping, which you can turn on. If the folder is duplicated, DrivePool will read from both drives and that can speed up the read task. If you expand the performance tab, you can see both drives that DrivePool is reading from and the speed at which it is reading. You can almost double the read speed in some transfers.
What I see on my system is that DrivePool will read from both my SSD and an archive HDD at the same time, but since the SSD is just so much faster, most of the read data comes from the SSD. I don't know if DrivePool is specifically programmed to recognize the faster drive and use that pipeline first, but in effect that is what I see happening on my system. My read speed, with Read Striping turned on, in those cases is almost exactly the same as the read speed on my SSD.
FYI, I only have 1 SSD, so I do not know if DrivePool would Read Strip both of your SSDs and almost double your read speed from the SSDs. Also, in my case, the bottleneck on my transfers is not the DrivePool read speeds, it is the speed of which I can transfer the data over my home network ethernet, the wifi, or to maybe a destination USB HDD. In most of my cases, transfers on my system are slowed down by lots of things but DrivePool is not one of them.
 

The auto refresh of Windows File Explorer has been a long standing issue with Windows. There are a number of fixes for this issue posted on the internet, but every version of Windows 10 seems to have a different solution. I personally just live with inconvenience because the next Windows update could "un-fix" the problem you thought you had solved. I don't have enough time in my day to manually apply "fixes" to Windows that might be wiped out next week on an update.
So, if I need to refresh File Explorer, I just hit F5 and it will refresh. I also use a third party File Manager and it has a refresh icon I click on and the directories are refreshed.
In short, I doubt your problems have anything to do with DrivePool as this is a known issue with Windows itself. But yes, I feel your pain as I go through this issue all the time on my computers. If you find a real fix to this issue, or if someone else has the solution, then we would all be happy.

Another option to consider may be using a product like PrimoCache which can use both your system RAM as level 1 cache and you SSD as level 2 cache for all your computer reads/writes - so, not just limited to DrivePool. DrivePool will use the SSD cache for writes only, but does not use it for caching reads. PrimoCache is a try before you buy software, and I think they offer a 30 day trial period. It worked good for me, but I chose just to use the DrivePool SSD plugin which is all I needed for my DrivePool home media server.
If you decided to go with something like PrimoCache, then you would not have to partition your SSD for multiple pools in DrivePool. In theory, you would have access to the entire SSD for every drive in your system and nothing wasted sitting in a partition that is not being used. Additionally, it is possible to overrun your DrivePool SSD cache if your data transfer is larger than your available space on the SSD. That has never happened to me, but evidently it is possible in DrivePool. With PrimoCache, on the other hand, it is more like a true buffer and you would not be able to overfill it. If you ever filled the PrimoCache buffer, the data would slow down/stop until more buffer space was available.
 

I ran Windows Storage Spaces for ~7 years before I moved to DrivePool. IIRC, Windows locks out all access to the pool drives in Storage Spaces, and as you stated, the best you get is one large drive displayed with most programs. At that time, I don't think I was able to get any disk monitoring programs to work with my Storage Spaces pool of drives.
If StableBit Scanner does not work well with Storage Spaces, you might want to download the free version of Hard Disk Sentinel to see if that program can detect the individual drives in the Storage Spaces pool. I know Hard Disk Sentinel detects all my pool drives in DrivePool and none of them have drive letters assigned. But, that may not be the same as Storage Spaces which takes total control over the drives because of the packet writing feature of Storage Spaces. It's worth a try and won't cost you anything but a little bit of time to see if it works. Good luck.

I just got done watching a 720p movie and I don't think my stream ever got over 1 MB/s. When I said the 1080p stream was 4 MB/s tops, that is maybe a short burst at the start of the file which I assume is filling the Fire TV Stick's onboard memory cache and then, like you noticed, it drops below 1 MB/s. Since you see more or less the same streaming transfer rate that I do on my system, maybe you can see why I am always saying that I doubt if your problem with streaming is coming from DrivePool.
If I copy files to/from a remote computer to/from my DrivePool computer on my home network, I can reach 80 MB/s transfer rate. So, clearly, it's not DrivePool that is slowing down my system.
@Shane already suggested using the Windows Resource Monitor, which I access via the Task Manager. You should be able to view the data streaming from your Storage Spaces drive volume.
I use Kodi as my main media interface. If your DrivePool computer is on your network, it probably already has network sharing set on it. If not, turn on network sharing for your DrivePool drive (J: on my computer). Then, in Kodi, you need to add the media folder by going to the browse network command. Is it complicated? Well, it's a bit more complicated than Plex to setup, but I just like the Kodi interface better than Plex so I was willing to put a little more effort into the project.  I had to go online and search for Kodi tutorials on how to setup a network folder for Kodi, but following the directions, I got it to work without too much difficulty.
Just another thought comes to mind... I think you once mentioned that you were using IP6 protocol for wifi. IIRC, I had all kinds of problems with IP6 and shut it off so I only use IP4. At the time, there were many people complaining about the IP6 protocol not working correctly. It might have been too new and the IP6 standards were not firmly set. Anyway, going back to IP4 worked for me and I have not changed it since (if it ain't broke, don't fix it). If you are using IP6, you might want to turn that off and see if the older, more stable, IP4 works better for you. It could be that your devices are trying to communicate via different versions of IP6 and they have a hard time talking, which would lead to dropouts. Anyway, just a thought.

Have you determined what speed your TV streaming device pulls movies from your Storage Spaces or DrivePool? For example, when I watch my DrivePool GUI, I can see that my Fire TV Stick is pulling about ~4 MB/s tops for streaming 1080p movies. I don't suffer any stuttering or caching on my system. If I try to stream movies >16GB, then I start to see problems and caching issues. But, at that point, I know I have reached the limits of my Fire TV Stick with limited memory storage and its low power processor. It is not a limit of how fast DrivePool can send data over my wifi.
Well, there is how many bars are available to indicate how strong the connection is, but bars does not equal speed. On my old 56K router, I would also have 4 or 5 bars indicating a strong connection, but I was constantly fighting buffering issues while streaming. I upgraded to a 1 gigabit router, which is much faster, and that took care of my buffering problems.
Well, good questions but beyond my level of tech expertise with that equipment. I get my internet service from a local telephone company, and they have a computer support team on staff to answer questions and help customers with their equipment. If you are leasing your equipment from ATT, then they might have a support team you could contact for assistance.
 
At least you have something that is currently working for you, so it's not like you are in a panic. After years of running Storage Spaces on my system, and now with DrivePool for just less than 1 year, I don't yet understand why you are experiencing streaming issues with DrivePool. On my system, it made no difference at all in regards to streaming, which I have stated runs at about 4 MB/s tops and usually much less on my system.

Have you determined what speed your TV streaming device pulls movies from your Storage Spaces or DrivePool? For example, when I watch my DrivePool GUI, I can see that my Fire TV Stick is pulling about ~4 MB/s tops for streaming 1080p movies. I don't suffer any stuttering or caching on my system. If I try to stream movies >16GB, then I start to see problems and caching issues. But, at that point, I know I have reached the limits of my Fire TV Stick with limited memory storage and its low power processor. It is not a limit of how fast DrivePool can send data over my wifi.
Well, there is how many bars are available to indicate how strong the connection is, but bars does not equal speed. On my old 56K router, I would also have 4 or 5 bars indicating a strong connection, but I was constantly fighting buffering issues while streaming. I upgraded to a 1 gigabit router, which is much faster, and that took care of my buffering problems.
Well, good questions but beyond my level of tech expertise with that equipment. I get my internet service from a local telephone company, and they have a computer support team on staff to answer questions and help customers with their equipment. If you are leasing your equipment from ATT, then they might have a support team you could contact for assistance.
 
At least you have something that is currently working for you, so it's not like you are in a panic. After years of running Storage Spaces on my system, and now with DrivePool for just less than 1 year, I don't yet understand why you are experiencing streaming issues with DrivePool. On my system, it made no difference at all in regards to streaming, which I have stated runs at about 4 MB/s tops and usually much less on my system.

You have not stated how much data you have in your DrivePool. I just use the default DrivePool Balancers, and over time, the drives will fill up with data more or less equally. If you just started moving data onto DrivePool, it may be that not all drives have been used yet. The DrivePool GUI gives a visual graph of the usage of your drives. If there is not much difference, I would not be concerned.
If you see one drive half full and another empty, then you might need to check which Balancers you have turned on and your Balancing settings in the DrivePool GUI. I have my settings to automatically balance the drives as needed.