Help Using Robocopy to Duplicate NAS Before Upgrade


I have a Synology DS412 NAS that is 93% full.  I have four 2 TB Western Digital Red Drives configured in a single RAID 6 volume with an effective size of 4 TB.  I want to increase my storage capacity by replacing the four 2TB drives with two mirrored 8TB drives.  

I do not have enough room on my server or on any PC to copy the 3.5TB of data that is currently on my NAS.  So I have a separate, brand new WD 8TB external USB3 drive I want to use as a temporary place to store all my data.  My plan is to

1. Backup my NAS to this external drive
2. Backup my current NAS configuration file, just in case
3. Pull the four 2TB drives from the NAS (it is hot swappable but I will likely do this with the NAS powered down)
4. Install two 8TB drives and set them up in RAID1 mirror, create volume labels and user accounts
5. Copy my backup from Step 1 to the new NAS.  

The trick is I need the files in the end to maintain all their original attributes including security, ownership, date stamps, etc. I do not want to lose any files (including hidden or system) and want all dates and paths to match the original.  I also want to be sure I did not lose anything in the transfer.

In an attempt to do this using another external HDD I ran CMD from my server as an admin and used the following syntax:

"C:\CopyRite XP\robocopy.exe" \\\Source\ F:\Destination /V /TS /S /E /COPY:DT /XA:HS /ZB /NP /FFT /XJD /R:1 /W:2 /DCOPY:T /LOG:"C:\1Robo\Pdrivelog2.txt" /V /TEE

I learned after the fact that over 6 thousand files were skipped.  After doing much digging, I realized that many of the problems came from the  /XA:HS command.  All of my hidden files as well as system files were skipped.  I identified over 2,500 Thumbs.db files that as system files were skipped, for example.  I do not know if simply deleting  /XA:HS will solve all of my problems.  Since the backup process takes close to 24 hours to run, I want to make the next run be the last.  I also want to avoid the need to returning the NAS to its current 2TBx4 config to recover lost or broken files.

Note: When I run the robocopy backup there will be no other users accessing any of the files on the NAS. I should not have any problems with open files being skipped.

Here are my questions:

1.  Since I will be using a brand new external HDD, should I use /E or /MIR?
2.  I don't think I should be using /COPY:DT.  Should I use /COPYALL, /COPY:DATSOU, /COPY:DATSO or something else? From my limited research I am leaning towards /COPY:DATSO
3.  I plan to drop  /XA:HS. Should I also drop /XJD?
4.  I will be running RoboCopy XP027 from my server that is running Windows Server 2012 R2. Is this the correct version to use?
5.  Is there a way for the log file to only list any files that were not successfully copied, along with summary stats?  Rather than see a huge log with 200,000+ lines in it, I only want to see files that did not copy.
6. Should I use the multi-thread capability to speed up the copy?  If yes, should I use /MT or /MT:12 or some other number.  Accuracy is more important than speed, if using /MT has any chance of introducing problems, I would rather wait.

Thanks in advance for your help!

EDITS: Since I posted I learned about the /L option.  I ran some tests and came up with the following proposed syntax that seems to not skip any files:

"C:\CopyRite XP\robocopy.exe" \\\SOURCE\ F:\DESTINATION /E /COPY:DATSO /DCOPY:T /ZB /NP /FFT /R:1 /W:2  /LOG:"C:\1Robo\log.txt" /V /TEE

Please comment on above.  I also learned I was using XP026.  When I tried XP027 it seemed to work, but the TEE output was not formatted as one file per line, it was a continuous string of test.  Using /MT did not seem to help with XP027, but again I was running /L and it may be useful when actually writing files.
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Seth SimmonsSr. Systems AdministratorCommented:
what about mirroring the folder structure?

robocopy <source> <destination> /mir /sec /secfix /r:1 /w:2

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MrChip2PresidentAuthor Commented:
Hi Seth, thank you for your comments.  Your answer seems to be a lot simpler.  I have read there are some tricky pitfalls to avoid using mirror, but I assume this would be 100% safe since I will be using this only one time on a clean drive, correct?

Just a few other questions, by using /SEC vs /COPY:DATSO what happens to the ownership information?  Will all the files be owned by everyone? admins or no one?

Also some of my files have very long file names and paths.  Should I add /FFT or will /MIR be able to handle them?
Seth SimmonsSr. Systems AdministratorCommented:
I have read there are some tricky pitfalls to avoid using mirror

what did you read?  i used this recently and had a few files error out though haven't had time to research why

by using /SEC vs /COPY:DATSO what happens to the ownership information?

/sec copies files with security; /copy:datso is the same as /sec but includes ownership
you can use /copyall to include all of those flags and maintain ownership

Also some of my files have very long file names and paths.

robocopy can handle this natively; no other switches needed
i had tested this on our old NetApp (which will migrate to windows soon) that has a few folders beyond 260 characters and it copied it fine; it's the client that has the issue with the long name (fixed in windows 10)
MrChip2PresidentAuthor Commented:
Thanks for your help.  I ran robocopy on the NAS with no errors and am going to do the HD upgrade today.
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