?
Solved

Number of Quorum Drives

Posted on 2006-03-29
3
Medium Priority
?
523 Views
Last Modified: 2013-12-27
I am in need of Sun Cluster Formula to determine the number of Quorum Drives needed based on the number of nodes.
I was unable to find it in the manuals. Can anyone assist? Thanks in advance.
0
Comment
Question by:MaxAix
  • 2
3 Comments
 
LVL 38

Expert Comment

by:yuzh
ID: 16328253
It depends on your hardware, please have a look at the formula and diagrams  in:
http://www.sun.com/bigadmin/features/articles/install_cluster.html

also this docs man help you to manage  Sun Cluster:
http://docs.sun.com/app/docs/doc/819-0580/6n30eahc7?a=view
0
 

Author Comment

by:MaxAix
ID: 16333951
I have one set of 4 cluster nodes(V240) and then the other set of 4 cluster nodes (15K).
I want to know SUN's recommendation for the number of quorum drives for each set of cluster.
The doscs you mentioned just specify the diagrams for the configurations but am unsure which one I should follow for my hardware. Please advice at the earliest. Thank you!
0
 
LVL 38

Accepted Solution

by:
yuzh earned 1500 total points
ID: 16338589
It is in my first link, eg:
Understanding Quorum

To form a cluster and offer services, the nodes in a cluster must first reach quorum. The quorum equation states that a cluster must have the total number of configured votes, divided by two (remainders are discarded), plus one (Q = TCV/2 + 1). If a cluster cannot reach quorum, then it does not form. The individual cluster nodes do not boot fully, but wait until enough votes are available to reach quorum. If a running cluster loses quorum, the affected nodes panic and try to reboot (assuming auto-boot? is set to true on those nodes). Machines can be booted outside the cluster by issuing a boot -x from the OBP, but no cluster services will be available on these machines.

The key to understanding quorum is learning how votes are assigned and counted. Each node in a configured cluster has one (1) quorum vote. Each shared storage device configured as a quorum device has votes totaling the number of connected devices minus one (QD = TCD - 1). Ownership of a quorum device is assigned to one controlling node based on SCSI reservations.

By doing some simple math, it's easy to see that a two-node cluster must have a quorum device to continue operating if one node fails. Once installed, a two-node cluster under Sun Cluster must have a quorum device for this very reason.

Quorum required to operate:

Q = TCV/2 + 1 = (2)/2 + 1 = 2

Votes if one node fails: 1
......

Please spend a few minutes to read the "Understanding Quorum" part.


Consider the following points when you plan quorum devices.

Minimum – A two-node cluster must have at least one shared disk assigned as a quorum device. For other topologies, quorum devices are optional.

Odd-number rule – If more than one quorum device is configured in a two-node cluster, or in a pair of nodes directly connected to the quorum device, configure an odd number of quorum devices. This configuration ensures that the quorum devices have completely independent failure pathways.

Connection – You must connect a quorum device to at least two nodes.

For more information have a look at:
"Quorum and Quorum Devices":
http://docs.sun.com/app/docs/doc/817-6537/6mltts63l?a=view

and

http://docs.sun.com/app/docs/doc/817-6536/6mltstlh9?a=view

Have a nice weekend!
0

Featured Post

VIDEO: THE CONCERTO CLOUD FOR HEALTHCARE

Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Using libpcap/Jpcap to capture and send packets on Solaris version (10/11) Library used: 1.      Libpcap (http://www.tcpdump.org) Version 1.2 2.      Jpcap(http://netresearch.ics.uci.edu/kfujii/Jpcap/doc/index.html) Version 0.6 Prerequisite: 1.      GCC …
Why Shell Scripting? Shell scripting is a powerful method of accessing UNIX systems and it is very flexible. Shell scripts are required when we want to execute a sequence of commands in Unix flavored operating systems. “Shell” is the command line i…
Learn how to get help with Linux/Unix bash shell commands. Use help to read help documents for built in bash shell commands.: Use man to interface with the online reference manuals for shell commands.: Use man to search man pages for unknown command…
Learn how to find files with the shell using the find and locate commands. Use locate to find a needle in a haystack.: With locate, check if the file still exists.: Use find to get the actual location of the file.:
Suggested Courses
Course of the Month15 days, 22 hours left to enroll

850 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question