To understand the dataflow in cluster-mode, one needs to understand the four major software components along with other key software components on every node in the cluster, they are as follows:
a. N-blade, network "blade"
b. D-blade, data "blade"
c. SCSI-blase, SCSI SAN "blade"
d. M-host, Management blade
Other components:
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-The cluster session manager (CSM)
-RDB units, which is the volume location database
All the above mentioned components are accessed only by well-defined application APIs. The N-blade and SCSI-blade translates client requests into Spin Network Protocol (SpinNP) requests. THe D-blade contains the WAFL file system that handles the SpinNP requests. The CSM is the SpinNP layer between the N-blade, the SCSI-blase and the D-blade.
Key Concepts:
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N-blade: The N-blade handles the networking, NFS and CIFS requests and then translates to SpinNP requests as inputs to CSM
SCSI-blade: The SCSI-blade handles the networking, FC, FCoE and iSCSI requests and then translates to SpinNP requests as inputs to CSM
CSM: CSM then acts as a communicator between N-bade or SCSI-blade SpinNP requests and input them to the D-blade over UDP/IP
D-blade: The D-blade which contains the WAFL file systems then handles the SpinNP requests and them communicate disks and tape devices using FC
Dataflow on a local node:
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1. NAS or SAN clients sends the write requests to a data logical interface (LIF)
2. N-blade (NAS) or SCSI-blade (SAN) which are associated with that LIF translates the NFS or CIFS, FC, FCoE, or iSCSI request to a SpinNP request
3. The SpinNP requests then passed to the D-blade via CSM
4. D-blade then sends the data to NVRAM and to the disks
5. The acknowledgments then works its way back to the client
Dataflow on a Remote node:
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1. NAS or SAN clients sends the write requests to a data logical interface (LIF)
2. N-blade (NAS) or SCSI-blade (SAN) which are associated with that LIF translates the NFS or CIFS, FC, FCoE, or iSCSI request to a SpinNP request
3. The SpinNP requests then passed to the "remote" D-blade via CSM
4. D-blade then sends the data to NVRAM and to the disks
5. The acknowledgments then works its way back to the client
