New to all of this, so is it unusual to not see data appearing on the drive that is being rebuilt, while the rebuild in running?

As the Parity and the other drives have a lot of reads and writes, and the rebuilding drive has almost all writes, but no data is showing on the rebuilding drive, either by mounting and reading the drive via linux commands or by trying to view with unraid. I did something stupid and formatted one of the drives, (don't ask why, as I said STUPID).  So made unraid see it as a new drive. Only about 1.5 hours to completion of the rebuild, says unraid.  I hope I did not do something else stupid.

According to the syslog, all drives are mounted as disks and they are in the correct slots.

 

Thanks in advance, Vic 

New to all of this, so is it unusual to not see data appearing on the drive that is being rebuilt, while the rebuild in running?

As the Parity and the other drives have a lot of reads and writes, and the rebuilding drive has almost all writes, but no data is showing on the rebuilding drive, either by mounting and reading the drive via linux commands or by trying to view with unraid. I did something stupid and formatted one of the drives, (don't ask why, as I said STUPID).  So made unraid see it as a new drive. Only about 1.5 hours to completion of the rebuild, says unraid.  I hope I did not do something else stupid.

According to the syslog, all drives are mounted as disks and they are in the correct slots.

 

Thanks in advance, Vic   

If you formatted a drive, you are not rebuilding it.

 

If you set a new disk configuration, you immediately invalidated parity, so no re-construction is possible.

 

Since you did not go into any detail or supply a syslog for analysis, not further help is possible other than to say if the drive has not failed you can probably use the

reiserfsck --rebuild-tree -S dev/mdX

to recover what was on it (or most of it anyways)