Basics and Data flow in NetApp Clustered Data OnTAP

1

 Similar to 7-mode we have three administrative privilage levels: admin, advanced and diagnostic. Clustered ONTAP system can be managed either from CLI or GUI (system manager or element manager). There are three different shells available with different scopes: Clustershell, nodeshell, systemshell

Step:1 Access through CLI

Clustershell:
=========
-SSH is default method
-One can access clustershell using cluster management LIF (recommended) or the node management LIFs
-Scope: entire cluster

LIFs Management: ‘net int show‘ with display the output of available cluster management and node management LIFs along with their IP’s, current node, current port and status

 

Nodeshell:
========
-Access nodeshell within the clustershell
-Scope: limited to one node at a time
-Command to access nodeshell is:

system node run

Systemshell:
=========
-Access systemshell from within the clustershell
-This is to access BSD shell
-Scope: single node at a time
-To access systemshell:

a. security login unlock -username diag
b. system node systemshell
c. Login as “diag”

Step:2 Access through GUI

-Start the system manager client using the IP address of the cluster management LIF
-This is well known interface to all the existing 7-mode administrators and I don’t think more explanation is needed here

Dataflow in NetApp cluster-mode

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:
==============
-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:
============
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:
===================
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

data flow

Dataflow on a Remote node:
=====================
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

 

data flow-2

 

Ravikiran Paladugu

Ravikiran Paladugu

Ravi pursuing his doctoral degree in the area of Data Science and currently working as a Storage and Hadoop consultant specializing in Apache Hadoop, EMC and NetApp products, USA. My experience with Big data includes design, deployment and administration of Hadoop and related components by providing end-to-end data protection and identifying performance bottlenecks in the infrastructure.

3 Responses

  1. Mike Garcia says:

    Great article. Thanks for the clarification!

  2. Rajasekar says:

    Excellent article :)

  3. yes this is what i expect

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