We're about to replace our old FAS3140 MetroCluster (streched, single location) with a brand new FAS8040 CDot MetroCluster, half on premises and half hosted.
Moving from a dual controller 7-Mode MC to a 4 nodes CDot MC raises a number of questions.
Having a dual controller box on each location somewhat makes sense, and I guess NetApp had to go this way to fend off arguments about the alleged lack of local resiliency of 7-Mode fabric MetroClusters.
Howerver, what really annoys me is the need to split our storage capacity among the 4 nodes.
I understand that it's still better than a few months ago, when each node had to use a dedicated pair of shelves, and the minimum setup for a CDot MC was 4 FAS8040 nodes and 8 DS4246 shelves (plus 4 FC switches, 4 FireBridges, and so on).
Now we've been told that shelves can be "shared" among nodes, and the minmum setup has been lowered to just 4 nodes and 4 shelves.
Still, this setup implies the use of small aggregates (~10 drives) and many dedicated spare drives. (I've read that CDot wants 2 spare drives per node for garage something ?!?)
Really, is there no way to avoid splitting the storage pool in 4 quarters ?
Can't the secondary node on each site be put in a standby mode, without dedicated storage ?
Can't we use "root-data partitionning", like is being done on FAS2500s ? (http://community.netapp.com/t5/Technology/Clustered-ONTAP-8-3-amp-Advanced-Drive-Partitioning/ba-p/98529)
Or is it coming anytime soon ?
And can't spare drives be shared among nodes ?