We have two nearly identical 6.5 servers that we're rolling into production.
The one, when we tried to use the big RAID5 array for the first time, had a
hard disk fail. The drive was replaced, the array rebuilt, and everything
seems to work fine with one notable exception:

If I run NSSMU, VOLUMES, and create a new volume in my RAID5 pool, I get
error -606, Error adding pool to NDS, when I hit Create. However, the
volume is always successfully added to NDS. Just now, I created TEST as a
volume, then went into nwadmn and saw it - it didn't appear in NDS until I
had hit <enter> on the error message in NSSMU.

I was able to delete the volume without a problem.

What's going on here? DSREPAIR, full unattended, shows zero problems, and
the server appears to work fine.

The other server does not give these errors when creating volumes.