Christopher (Drashna)

Mostly, yes.
If it's a new file, yes, it's smart enough, and will work correctly.  
But modifying a file.... it doesn't use the SSD for that. 
Also, the duplication happens at a specific time each day. So the file isn't protected for up to 24 hours.  Even longer if the file is open, as we cannot duplicate open files.  (one of the reasons we recommend not turning off real time duplication)

If you mount the pooled drives to folder paths, ... you may only need to run it once, then.

With most of the topics here targeting tech support questions when something isn't working right, I wanted to post a positive experience I had with Drivepool for others to benefit from..
 
There was an issue on my server today where a USB drive went unresponsive and couldn't be dismounted.  I decided to bounce the server, and when it came back up Drivepool threw up error messages and the GUI for it wouldn't open.  I found the culprit - somehow the Drivepool service was unable to start, even though all it's dependencies were running.  The nice part is that even though the service wouldn't run, the Pool was still available.  "Okay" I thought, and did an install repair on Stablebit Drivepool through the Control Panel.  Well, that didn't seem to work either - the service just flat-out refused to start.
So at that point I assumed something in the software was corrupted, and decided to 1) Uninstall Drivepool  2) bounce the server again  3) Run a cleaning utility and 4) Re-install.  I did just that, and Drivepool installed to the same location without complaint.  After starting the Drivepool GUI I was greeted with the same Pool I had before, running under the same drive letter, with all of the same performance settings, folder duplication settings, etc that it always had.  To check things I ran a re-measure on the pool, which came up showing everything normal.  It's almost as if it didn't care if it's service was terminal and it was uninstalled/reinstalled.  Plex Media Server was watching after the reboot, and as soon as it saw the Pool available the scanner and transcoders kicked off like nothing had happened.
Total time to fix was about 30 minutes start to finish, and I didn't have to change/reset any settings for the Pool.  It's back up and running normally now after a very easy fix for what might seem to be an "uh oh!" moment.
That's my positive story for the day, and why I continue to recommend Stablebit products.

Sorry for not getting back to you on this! But glad to hear that it sounds like it's mostly resolved (by a bunch of disk checks?)
 
We've .... spent a LOT of time on that section of code for StableBit DrivePool.  Not just moves, but deletes as well.  NTFS does some "weird" stuff, and it's cause issues in the past.
That said, if you're able to reproduce this sort of issue, that would be awesome.  Especially, "at will".
http://wiki.covecube.com/StableBit_DrivePool_2.x_Log_Collection
http://wiki.covecube.com/StableBit_CloudDrive_Drive_Tracing
grabbing the drive tracing from this when it happens would be super helpful (as well as detailed instructions on how you triggered it).  This way, we can take a look at the logs and see what exactly happened. 

Yes, so say you have 2 HDDs and 1 cloud thing. What you could do is:
1. Create Pool O with 2xHDD, x2 dup
2. Create Pool P with the cloud thing as one drive and Pool O as the other, x2 dup
Anything you write to Pool O will be duplicated locally
Anythin you write to Pool Q will be duplicated, so one copy on O and one on the cloud thing, but... As Pool O is x2 dup itself, it will write to both HDDs, so x3 dup really.

For the remote control stuff, that's finicky, at best.  Network detection has always been "hit or miss", and not just for our software. 
I'm glad to hear that you did get it resolved though.
But worst case, you can always manually add entries: 
http://wiki.covecube.com/StableBit_Scanner_Advanced_Settings#RemoteControl.xml

Just wanted to give an update for those who have problems with xfinity new 1gb line - I basically had them come out  showed them how the line was going in and out with the pingplotter and they rewired everything and they changed out the modem once they did that everything has stabilized and  been working great - thank you for all your help guys! long live stablebit drive! lol 

Keep awake - get a copy of Stablebit Scanner and tell it not to throttle SMART queries so the drive stays awake.  Or use the USB drive's utilities to set it's sleep timer.  Drivepool just manages the pool and allows disks to spin down if that's how their firmware or Windows is set. 
As far as balancing goes - I turn off automatic balancing so files always stay where they were originally put.  Less wear and tear, less of a performance hassle if the server is being used.  New files are added to the disks with the most available space, bringing it back in line with continuing to be balanced.  If I ever see the balance on the disks being less optimal than I'd like, I kickoff a manual re-balance with the Disk Space Equalizer plugin and go to bed.  Really the only thing that kicks the pool out of balance for me is the Monthly Full & 3xx/week Differential backups I put on the drives.  And I don't care if it's slightly unbalanced because of them - it wipes the fulls every month, and it only keeps two copies of the differentials at any one time.  Plus - you can force those to specific disk(s) with file placement rules.
If you -want- to schedule periodic (nightly) rebalances, turn on "Balance every day at.." in the Balancing UI.
I think that Drivepool does a great job of balancing on it's own, and it's something that is easy for people to overthink.  Just disable automatics and manually do it when you want.
Edit:  I attached a screenshot of my pool drives - I haven't done a manual re-balance on it for over a month now, and probably won't for a long time.

I find Scanner almost essential now - I rely on it as a watchdog to keep my data safe, and to alert me to potential problems (heat, SMART errors, etc).  And I use it with the auto-evacuate balancer in Drivepool, so that IF it senses a drive might be dying it can move files off to other drives without needing me first.  Well worth the cost in my opinion, AND you can get additional copies of each product at a steep discount.  I run Scanner on both my server and primary workstation.

Yup.  Adding the drive to the pool doesn't move existing data into it automatically, so it won't break your config. 
Yes and no.   In theory, yes.  But the default balancers shouldn't move the data around in most cases. 
You can read about the default balancers here: https://stablebit.com/Support/DrivePool/2.X/Manual?Section=Balancing Plug-ins
And yes, the files can end up spread out, but the "File Placement Rules" feature can be used to help prevent that. 
Nope.   There is no linking or the like.   File lists are generated dynamically from the disks.  Basically, when you open a folder, it's queried, then DrivePool queries that location on each disk and combines them and returns with that combined list.  
The upside is that this means no links to maintain, and none of the issues associated with that. 
The downside is that the software doesn't maintain a list of the pool's contents.  
If Duplication and the Read Striping feature is enabled, then yes, it should be able to handle this in an intelligent way (eg, by avoiding busy disks, or reading the contents of files from multiple disks at the same time) 
https://stablebit.com/Support/DrivePool/2.X/Manual?Section=Performance Options#Read Striping
Otherwise, you should see very similar performance to just using the disk by itself, since the IO requests are basically just forwarded to the underlying disks. 
 
As for the frequently used files, sorry, no that isn't supported.  THe pool doesn't use the access, modified or created data, since that may not exist when the file is being created (in the kernel). 
 
Plex does a very unusual thing and uses file system hard links to create it's database, rather than using it's SQLite database to manage the files. 
That's the issue, actually.  Hard links only work on the same volume (disk).  And because of how they're stored in the file system, it doesn't work on the pool, at all. (if you're familiar with "cross linking" in file systems, hard links are this, but intentional)
Adding the C:\ drive to the pool is fine.  In fact, I do that with my desktop system.
The issue is that you CANNOT run Windows off of the pool.   The reason for that, is that there are "kernel drivers" and "boot drivers", and these are VERY different .... and the Pool driver is a kernel driver, NOT a boot driver.  So ... you'd have no way to read the pool until after booting. 
So yes, this would definitely cause Windows to fail to boot. 
StableBit DrivePool doesn't maintain a database, at all.   See my response to question #4. 
So, unless you experience drive failures, the files will still be there, and accessible. 
 
In fact, you could pull the drives, pop them into a new system, install StableBit DrivePool, and then IMMEDIATELY use the pool. 
 
C) it queries the relative location under the PoolPart folder on each disk, for that folder and it's contents. 
Specically, all of the data in the pool is stored in hidden "PoolPart.xxxx" folders (where "xxxx" is a long hexadecimal string called a "GUID").  
The pooled data is stored in the same relative path in this folder. 
So if we have a file "X:\Photos\2012\001.jpg" that is stored on the pool, and is duplicated, then it resides at:
Y:\PoolPart.xxxx\Photos\2012\001.jpg Z:\PoolPart.yyyyy\Photos\2012\001.jpg Basically, if you know the location of the file in the pool, then it's in the same location on the pooled disks, but under the PoolPart folder. 
How dare you! 
Just kidding! 
No, we totally understand that!   I've see that too....  And ... in fact Windows Home Server (v1) was very much like that. It's Drive Extender tech had a NASTY corruption bug on release... that they were informed of well prior to release.  So ... yeah. 
I can't say that our products are flawless (no software is), but we do try.  And we try to fix issues pretty fast, when we can. 
That, and don't worry about asking 100 questions. That's fine, and that's what I'm hear for.  
If you have more questions, feel free to ask here, or at https://stablebit.com/contact (I tend to respond faster there)

Nice - more tidbits of useful wisdom today!

As long as they have access to the account and files on it, and the drive isn't mounted already, then any system can access it. Even with different licenses. 
Yes: https://stablebit.com/Support/CloudDrive/Manual?Section=Setting your Drive as Read-Only
Not at this point, no. Sorry. 

Yeah, the colors can be blinding.... 
And I think I've had this conversation with Alex before.  The issue is that StableBit Scanner use a 3rd party UI suite, and I don't think they support a "dark" theme.  So it wouldn't be a small effort to add it. 
 
But yes, I'd like a "night mode" for all of our software, actually. 
https://stablebit.com/Admin/IssueAnalysis/27925

Yeah, I mentioned that in one of my edits - where it has Note: near the end.  It'd be very rare, though possible.   
Scanner has a free trial period - since you have the software RAID 0 in place, you could install and test.  You wouldn't need (and couldn't use) evacuation in that case since it was a 2x duplicated pool, though I find that feature of Scanner highly valuable, and in your case you could implement it with three 2-pair drives in each Duplication pool (12 total drives).  At the least, you could see if SMART data was being retrieved by Scanner successfully.
Very few (1 or 2?) SMART polling utilities were able to "see through" my LSI controller to the SMART info.  I think they really wanted people to be using the MegaRaid software they developed for it instead.

After some testing, Pool B follows Pool A's SSD Optimiser
You can close this thread, thanks for the help!

What @Jaga said, actually. 
And "coveFS" is the driver for the pool, so it's a critical component, actually. 
 
And it may be worth doing this: http://wiki.covecube.com/StableBit_DrivePool_Q3017479
And then reinstall the software. 
If you continue to have issues, then open a ticket at https://stablebit.com/contact 
and run the StableBit Troubleshooter: http://wiki.covecube.com/StableBit_Troubleshooter

Yup. 
How they work, and how Windows handles them, ESPECIALLY over a network.  
That looks right.
That depends on how you move the data, but yeah, this is likely what will happen.  If you move data from volume to volume, this is what happens.  You only get the "smart move" if the data is on the same volume. 
If the SSD Optimizer is enabled for that pool, yes.

They did offer an RMA, but ups ground shipping was going to cost me almost $90 so it’s going to the town dump instead. I have other arrays I’m using now and would rather use the money for the sas setup I’m planning on moving to. 

That should work, then.  Just wanted to make sure.
And yes, that would definitely need an SSD (and maybe even an NVMe based SSD) for that. 
If you want to use file placement rules AND the SSD Optimizer, there are some settings that you MUST change. 
 
Junctions.  If you have the option, always junctions.  Symlinks can be handled oddly in some cases.
And yeah, that software is nice
You can create multiple pools, actually.  That may be the best for what you want. 
But keep in mind that each disk can only be part of a single pool. 
 

1x128 SSD for OS, 1x8TB, 2x4TB, 2x2TB, 1x900GB. The 8TB and 1x4+1x2TB are in a hierarchical duplicated Pool, all with 2TB partitions so that WHS2011 Server Backup works. The other 4TB+2TB are in case some HDD fails. The 900GB is for trash of an further unnamed downloading client.So actually, a pretty small Server given what many users here have.

I'm simply glad I get to keep using Scanner as my pool monitor.  The thought of no Smart data and no Scanner...  yikes.

You'll need to disable the SSD Optimizer balancer.  
Do that, and see if it works (it should) 

First, is the database a single file?  
If so, then you can't split it.
Second, you could not use hard links, since these cannot span volumes.  You'd need to use junctions (ideally) or symblinks. 
 
 

Found a way to generate SMART data through the LSI adapter.  Funny thing is - it was lurking on the Covecube forums the entire time.   
Simply enable advanced settings in Scanner, stop/start the service, then turn on Unsafe DirectIO.  Problem solved.  And it only took 2-3 hours of research to bring me right back here.
Where's that facepalm emote when you need it?

The Disk Space Equalizer plug-in comes to mind.
https://stablebit.com/DrivePool/Plugins