Understanding difference between 7-mode and c-dot from a systemshell point of view

There is a huge difference in the way the Ontap shell communicates with the layer beneath.. In a 7mode all the configuration files are stored in the the /etc directory... for example: /etc/rc, /ect/exportfs, /etc/hosts..

But when it comes to cluster mode.. we have the files present.. but they are actually not really used.. Instead all the files are managed by the RDB (replicating database).. 

A replication ring is a set of identical processes running on all nodes in the cluster.

The basis of clustering is the replicated database (RDB). An instance of the RDB is maintained on each node in a cluster. There are a number of processes that use the RDB to ensure consistent data across the cluster. These processes include the management application (mgmt), volume location database (vldb), virtual-interface manager (vifmgr), and SAN management daemon (bcomd).

For instance, the vldb replication ring for a given cluster consists of all instances of vldb running in the cluster.

RDB replication requires healthy cluster links among all nodes in the cluster. If the cluster network fails in whole or in part, file services can become unavailable. The cluster ring show displays the status of replication rings and can assist with troubleshooting efforts..

Lets jump into the systemshell... and from there to the bash shell and exactly see how it is working.

PLEASE DON'T TRY IT IN PRODUCTION, UNLESS YOU KNOW WHAT YOU ARE DOING.

cluster600::*> systemshell

  (system node systemshell)

Data ONTAP/amd64 (cluster600-01) (pts/2)

login: diag

Password:

Last login: Fri Feb 12 11:33:17 from localhost

Warning:  The system shell provides access to low-level

diagnostic tools that can cause irreparable damage to

the system if not used properly.  Use this environment

only when directed to do so by support personnel.

cluster600-01%

cluster600-01%

cluster600-01% sudo bash

bash-3.2#

bash-3.2#

bash-3.2# cd /mroot/etc/cluster_config/rdb

bash-3.2# ls

Bcom            Management      VLDB            VifMgr

bash-3.2#

These are the four files that contain are contained in the RDB.. Can we change it.. Yes we can, but needs lot of understanding as how it works to do it.. I have tried doing it and it works.. but its a long process. The better option is to use the cluster command line.. that's the actual process.. 

In senarios when the there is a disaster this is the way to go.. 

In the next blog, I'll walk through the way how the junction path works and whats the difference when it comes to 7mode and c-dot

PLEASE WRITE BACK IF THIS WAS USEFUL.

Netapp monitoring solution from scratch

I created a netapp monitoring solution on a UNIX machine... and have uploaded the static files to a free php server for so that you understand how it looks..
As its a file server where the files are uploaded.. It is not exactly the one as on the UNIX machine.. but you could still get a feel of it.

Advantages:

• No third-party tools used like Nagios or PRTG or any other,
• Build from scratch.
• Fully customization.
• Any required parameters can be monitored.
• Complete look and feel can be changed as per user needs
• Easy to use.

If anyone is interested to know more about it, feel free to drop me a message.

Example Link:
This is for cluster mode.. I have done similar one for 7-mode as well... and in the live solution it monitors even the NFS and CIFS load from hosts connected to filer.. and also the detailed host load analysis.
nfs600_vol1 is the only volume which was used to write data from a server. So you would see load only on this volume.. This is a test netapp simulator which I have used in this solution.

http://anirvan_lahiri.net23.net/monitoring/monitor.php

netapp clustermode debug (debug vreport)

Aggregate troubleshooting with debug vreport

If there is an inconsistency between VLDB and WAFL on a local node,
you can fix that with “debug”

Create an aggregate in the nodeshell
This aggregate will be known in WAFL but not in VLDB

cl1::*> node run -node cl1-01
Type ‘exit’ or ‘Ctrl-D’ to return to the CLI
cl1-01> options nodescope.reenabledcmds “aggr=create,destroy,status,offline,online”
cl1-01> aggr create aggrwafl 5
Creation of an aggregate with 5 disks has completed.

Create an aggregate in the clustershell and remove it from WAFL.
This aggregate will then be known in VLDB but removed from WAFL.

cl1::>aggr create rdbaggr -diskcount 5 -node cl1-01
cl1::> node run -node cl1-01
Type ‘exit’ or ‘Ctrl-D’ to return to the CLI
cl1-01> aggr offline rdbaggr
Aggregate ‘rdbaggr’ is now offline.
cl1-01> aggr destroy rdbaggr
Are you sure you want to destroy this aggregate? y
Aggregate ‘rdbaggr’ destroyed.
cl1-01> exit
logout

Run dbug vreport.

cl1::> set diag
cl1::*> debug vreport show

aggregate Differences:
Name Reason Attributes
——– ——- —————————————————
aggrwafl(8e836c6d-76a0-4202-bb40-22694424f847)
Present in WAFL Only
Node Name: cl1-01
Aggregate UUID: 8e836c6d-76a0-4202-bb40-22694424f847
Aggregate State: online
Aggregate Raid Status: raid_dp

rdbaggr Present in VLDB Only
Node Name: cl1-01
Aggregate UUID: d7cfb17e-a374-43c6-b721-debfcf549191
Aggregate State: unknown
Aggregate Raid Status:
2 entries were displayed.

Fix VLDB ( aggregate will be added to VLDB )
cl1::debug*> debug vreport fix -type aggregate -object aggrwafl(8e836c6d-76a0-4202-bb40-22694424f847)

Fix VLDB ( aggregate will be removed from VLDB )
cl1::debug*> debug vreport fix -type aggregate -object rdbaggr
cl1::debug*> debug vreport show 
This table is currently empty.
Info: WAFL and VLDB volume/aggregate records are consistent.