clustermode architecture

N-blades are responsible for network part
(common internal protocol SpinNP)

D-blades are responsible for aggregates and volumes

M-host is responsible for clustermanagement

 
The volumes that are physically distributed across the individual D-Blades are “stitched together” into a global namespace by connecting them in to a directory in a “parent” volume at time of creation. This concept is depicted in figure 2.

Figure 2. Global namespace construction from distributed volumes

When a client request is made to the N-Blade, a quick, in-memory lookup is done (in the VLDB, or volume location database) to determine which node has the data for the requested file, and the request is “routed” (through the cluster fabric switch) to the appropriate D-Blade. (Think of the VLDB as a “volume router” — analogous to a network router, which caches its maps in memory for *very rapid* switching). The target D-Blade makes the appropriate storage request, and returns the necessary information to the N-Blade, which then returns it to the client. This all occurs over the SpinNP protocol, a lightweight RPC protocol engineered from scratch by the Spinnaker team to ensure low latency and efficiency of storage network operations.

So, bottom line … you spread the clients out the front, the data out the back, and leverage a scalable cluster fabric that allows you to scale controller performance and end-to-end client and storage network bandwidth as capacity scales. Furthermore, because the individual storage partitions are themselves scalable – from both a capacity and performance perspective, the architecture can provide a wide range of storage system characteristics – from “wide and thin” (high performance, low capacity) to “narrow and deep” (higher capacity, lower performance).

From the systemshell the mounted volumes can be seen by accessing /clus
sudo ls /clus/vs1/vol
vol1

From the clustershell you can unmount the volume
volume unmount -vserver vs1 -volume vol1

From the systemshell see that the volume is unmounted from the namespace
sudo ls /clus/vs1/vol
(vol1 is no longer there)
It is still online but no longer mounted