Robert -
I tried creating the mixed raid aggr on an 8.2 7-mode sim, and had success.
7m82a> aggr add test -t raid4 -g new -T SSD 8
Note: preparing to add 7 data disks and 1 parity disk.
Continue? ([y]es, [n]o, or [p]review RAID layout) p
The RAID group configuration will change as follows:
RAID Group Current NEW RAID Type
---------- ------- --- ---------
/test/plex0/rg0 8 disks 8 disks raid_dp
/test/plex0/rg1 8 disks raid4
I was also able to flip the raid type of the SSD tier back and forth from 4 to DP and back again:
7m82a> aggr options test raidtype raid_dp -T SSD
Aggregate test: cache raid group size is adjusted from 8 to 23 after changing raidtype.
7m82a> Fri Apr 18 02:33:29 GMT [7m82a:raid.config.raidsize.change:notice]: aggregate test:cache raidsize is adjusted from 8 to 23 after changing raidtype.
Fri Apr 18 02:33:29 GMT [7m82a:raid.rg.recons.missing:notice]: RAID group /test/plex0/rg1 is missing 1 disk(s).
Fri Apr 18 02:33:29 GMT [7m82a:raid.rg.recons.info:notice]: Spare disk v6.25 will be used to reconstruct one missing disk in RAID group /test/plex0/rg1.
Fri Apr 18 02:33:29 GMT [7m82a:raid.rg.recons.start:notice]: /test/plex0/rg1: starting reconstruction, using disk v6.25
7m82a>
7m82a> aggr options test raidtype raid4 -T SSD
Fri Apr 18 02:33:47 GMT [7m82a:raid.rg.recons.aborted:notice]: /test/plex0/rg1: reconstruction aborted at disk block 43264 after 0:18.11
Aggregate test: cache raid group size is adjusted from 23 to 8 after changing raidtype.
7m82a> Fri Apr 18 02:33:48 GMT [7m82a:raid.config.raidsize.change:notice]: Aggregate test:cache raidsize is adjusted from 23 to 8 after changing raidtype.
Fri Apr 18 02:33:48 GMT [7m82a:raid.vol.mixed.raid.type:info]: test is now a mixed RAID type aggregate.
Still not sure why the -T flag wasn't working for you earlier ?
I hope this response has been helpful to you.
At your service,
Eugene E. Kashpureff
Independent NetApp Consultant, K&H Research http://www.linkedin.com/in/eugenekashpureff
Senior NetApp Instructor, Unitek Education http://www.unitek.com/training/netapp/
(P.S. I appreciate points for helpful or correct answers.)