Hot Spares on V-Series

[ttrace_essence]

Greetings, looking for confirmation and second opinions --

I've got a V-Series 3240 HA pair running 8.0.2RC1.  Attached are 3x DS-4243 with 450GB 15K RPM SAS and 1x DS-4243 with 1TB 7.2K RPM SATA.  I expect to add another four DS-4243 with SAS drives by the end of 1Q2012.  I don't expect to add any more SATA disk.

At the risk of oversimplification, regarding the native NetApp disk, do I understand correctly that for proper protection each filer must own two SAS and two SATA spares?  And that as my system grows towards 168 SAS disks, I should maintain three SAS spares per filer?

And...the back-end storage (three seperate Clariion CX-3) will swap its own hot spares into RAID groups as necessary, requiring no direction from the NetApp filers?

Thank you ----

[lovik_netapp]

Yes, you need minimum 2 spare disk of each type on controller, but you don't need to keep spare if controller doesn't use that disk type. I mean if you have SATA disk on controller1 and SAS disk on controller2 then you need 2 spare disk of SATA on controller1 and 2 SAS spare on controller2, you don't need to keep 2 sata and 2 sas disk on each controller.

I believe you are using native disk and backend array both on your systems, so you need spare only for native disk and for your CX-3 system no spare is required and all the luns assigned to v-series from CX-3 are already in raid protection by clarion so V-Series dosen't have to worry about the spare disk.