Hi Experts,

Its been a long time to be here. Now, I'm again here with couple of questions. As usual, I got the help earlier, I'm expecting the same kinda thing this time also.

I'm working on redhat clusters (RHEL 5/6) from past few years but few of the options available with RHEL cluster, I have never used. Need you help/guidance on them. Please tell what is the exact use of them and when should one need to use them? Answers with example would be more appreciable.

Here are the options -

1) clusvcadm -s ( I know it is to stop the cluster, then why -d is there? And what is the functional difference between "stop" & "disable" options?
2) clusvcadm -Z (Its for Freeze, but why one should use this, and would be the impact if someone use this option?)
3) clusvcadm -U (Unfreeze :-S )
4) clusvcadm -c
5) Final one... Why should we add a multicast address in cluster (in case if we need to do so)?


Thanks in advance.

Your question is confusing...if you have been using Red Hat clusters for a few YEARS, how can you NOT know what the basics of cluster administration are? The man page for the clusvcadm command explains what the options are:
http://linux.die.net/man/8/clusvcadm

...and what they do. The differences between the -s and -d are clearly spelled out, as well as the -c option. Freezing and un-freezing a service is a common task, and covered well in the RHEL documentation?
https://access.redhat.com/documentat...ns-cli-CA.html

As far as multicasting goes...if you've been using clustering for a few years now, did you not research what it did, and why, before using it?

Hi TB0ne,

Thanks for your reply.

Sorry for the late response. I just came back from a long vacation.

Sorry if there any ambiguity in my questions.

Yes, I've been working on linux clusters for a while but it doesn't mean I should try all the available commands/options in production environment. I tried only those which I knows what it does (which usually accomlish my needs).


I know what is multicasting and what it does. May be I was not able to put my question properly. Let me put it in simple way ;-)

Usaually, we does setup or assign any multicast address to cluster nodes. We goes with default settings (system assigned multicast addresses). In our setup, I found couple of RHEL6 clusters where multicast IP addresses are defined exclusively in the /etc/cluster/cluster.conf file (the persons those have configured these servers are no more with company and nothing has been shared). (Note: I've found couple of old mails sent by those guys within the team which suggests that they had requested for multicast addresses from network team).

So, my question is, if the cluster can be setup/configured with default multicast settings, then why someone needs to set it up manually?

ex:

<clusternodes>
<clusternode name="xxx.com" nodeid="1" votes="1">
<fence/>
<multicast addr="xxx.x.x.x"/>
</clusternode>
<clusternode name="yyy.com" nodeid="2" votes="1">
<fence/>
<multicast addr="xxx.x.x.x"/>


Thanks.