Upgraded from v5.0.4 to v6 beta12, have several questions.

OK, I upgraded and it looks like it was successful.  A cursory check appears to show that all my data is available.  Parity check is being done right now.  Upgraded for various reasons.  Primary use for unRAID Pro server is NAS and Plex server.  I'd also like to get Couch Potato, SickBeard and SABnzbd working.  I'm a total Linux noob and the only way I had a stable server was by following people's instructions to the letter.  If there was decent documentation somewhere, I could probably stumble through this, but it seems that these forums are the only source of support.  I've tried searching for the answers, but I'm either not finding them or I'm unable to understand them.

My questions:

1.  I had an SSD mounted outside the array as an appdisk using the method found here: http://lime-technology.com/forum/index.php?topic=30496.0  I understand that since then, SNAP has been determined to be the way to go, but I've also gathered that using the cache drive is also popular.  Right now, my appdisk is still available outside the array.  What are the advantages and disadvantages to leaving the appdisk as it is, modifying it to use SNAP, or making it part of the cache pool?

2.  Speaking of cache pool, I have a large SSHD drive that I'd like to add to the cache pool, regardless of what I do with the SSD appdisk, but I'm finding it very difficult to figure out how to add drives to the pool.  Are there limits to the number of drives that can be added to the cache pool?  How in the world do I do this?

3.  I've tried to start the Docker service, but I'm unable to save the Docker image to my appdisk.  I'm completely clueless where to go from here. 

I'm really glad that I've not lost any data, but I would appreciate a few pointers in getting the other stuff working again.

Thanks in advance!

Oh, yeah, one more question:

My drives are still formatted with ReiserFS. 

Is it possible and/or desirable to reformat the Array drives?  If there are definite advantages, I'll buy new drives in order to be able to move data around.

I would think the cache drive would be easier to empty.  Advantages? 

If I should reformat, how? 

Thanks and sorry for the noob questions.

There are no obvious advantages to moving off Reiserfs except for the fact that at some time in the future support for it might be discontinued.  Also the lack of developer support might mean it is more susceptible to having bugs in new kernel releases.

I would suggest that you have a plan to move, but there is no urgency.  One possible downside is that once you have converted drives then you can no longer revert to v5.

Good to know about the file system and lack of urgency.  Hopefully I can sort these other issues out first, but I think I'll order a HDD and utilize this method once it gets here:

Whether you are moving to XFS or BTRFS (I am moving to XFS personally), there is no quick and easy method.

 

What I did was started with a new disk of the largest size in my array formatted with the new FS (XFS for me).

 

I use Teracopy in move mode (Teramove) using my Windows workstation. Teramove will copy the file (determining its hash code in the process), and afterwards read the destination file to determine its hash code. Only if the hash codes match does Teramove delete the source file start the next file. Thus your move is self verifying. It DOES take longer, but I am confident that the move worked properly (see below for a known risk). Once the disk is moved completely, reformat the now empty disk to the new FS, and then began the process of Teramoving the next disk to it. Repeat until all of the disks are moved over. At the end you should have an empty disk left over.

 

Note that difference file systems have different amounts of housekeeping, so if you fill your disks to the brim, you may not have enough space for the last few files to fit on the new FS. You can deal with this preemptively, by moving some files to a less full disk to leave at least a few gigs of free space on your source disk before you start the move, or just let it go and clean up if it fails near the end.

 

There is a suspected bug (I am about 90% confident based on personal experience) that if you are copying a file at the time the destination disk is red-balled by unRAID, the file it was copying will be corrupted. If you are moving the files from disk to disk (the fastest method), you would never know. The Teramove will detect that this happened and stop, and will NOT delete the source file. (Note that if anyone has this happen, please contact me via PM. I would ask you to run some tests on the source and target files to try and verify this is indeed a bug).

Still have to figure out how to actually reformat a disk once it's empty, but I think that's in the setup tutorial.

As an update, the parity check finished overnight and the results are:  Last checked on Fri 02 Jan 2015 02:57:22 AM CST (today), finding 0 errors.

? Duration: 11 hours, 1 minute, 50 seconds. Average speed: 100.8 MB/sec

So, that's good.  I think that makes everything else not an emergency, but I was hoping to finish it up over this weekend before I go out of town for a couple of weeks.

If anyone has any ideas or can point me in the right direction on my docker, cache pool and appdisk questions, that would be awesome. 

Still have to figure out how to actually reformat a disk once it's empty, but I think that's in the setup tutorial.

If you stop the array then you can click the disk on the main tab and change the format for the disk.  On restarting the array the disk will show as unformatted and you will be offered the option to format it to create an empty file system in the new format.  Once formatted you can start copying files onto it.

Still have to figure out how to actually reformat a disk once it's empty, but I think that's in the setup tutorial.

If you stop the array then you can click the disk on the main tab and change the format for the disk.  On restarting the array the disk will show as unformatted and you will be offered the option to format it to create an empty file system in the new format.  Once formatted you can start copying files onto it.

I see.  Thanks for your help!

Well, I just ordered a 6TB HDD to replace my Parity drive.  Hope that's pretty straightforward.  Once that's replaced, I'll begin reformatting my data disks.

Got Plex working using Phaze' plugin. Data's safe and wife can watch TV, so I'm happy.  I'll work on the other stuff in a few weeks. Should have a new parity drive to install.