SUMMARY: Breaking up a cluster

From: Spalding, Stephen <SSpaldin_at_mem-ins.com>
Date: Fri, 18 Feb 2000 12:10:20 -0600

My original email read:

"This weekend I am planning on splitting up my cluster of two Alpha Server
> 4100s into two standalone boxes. Right now, both Alpha Servers are on a
> differential bus with two sets of dual redundant HSZ50s using TruCluster
> 1.5, and the idea is that each Alpha Server will get one set of HSZ50s.
> What
> I'd like to do first is leave the TruCluster software running and just
> remove the cable connection between the two sets of HSZ50s. After removing
> the cable that connects the HSZ50 sets, I will go into asemgr on each host
> and remove the other host as an available member. Once I have done that
> and
> am satisfied that it works (probably next weekend), I will remove the
> TruCluster software.
>
> My first question is, what else do I need to look out for after removing
> the
> hosts from asemgr and removing the connecting cable?
>
> My second question is, once I am ready to remove the TruCluster software,
> what commands do I use to remove it? I don't believe that it's as easy as
> simply removing the software subset using setld -d.
>
>
> My third question is, once the TruCluster software is removed, how is this
> going to affect my device names on UNIX? The differential SCSI bus ID is
> 16,
> and my UNIX device names are rz128, rz129, rz132, and rz133. Will these
> return to rz0, rz1, rz4, and rz5?
>
> My last question is, what else do I need to be on the lookout for when
> removing the TruCluster software?"
>
I got several nice responses, but the one that helped the most came from Jim
R. Jones who said to put the following two lines in /etc/sysconfigtab:

> clubase:
> cluster_disable=1
>
This disables the cluster from coming up once rebooted. I also got a good
little excerpt from Wendy Fong on SCSI device naming:

        An rz25 designation is determined by:
        # uerf -R -r 300
        rz25 AT scsi3 target 1 lun 0
        _(DEC HSZ50-AX V51Z)


        Where, nexus is scsi bus=3, target=1, LUN=0


        rz + LUN letter + (8 x scsi # + target) (lun number 0 -> 7
corresponds to a -> g)
        rz + a + (8 x 3 + 1) = rza25 or rz25 (It seems they drop
the 'a' and use from 'b' forward)

As far as the TruCluster software, you simply use setld -d to remove it.
Thanks to everyone who responded.

-Stephen Spalding
Received on Fri Feb 18 2000 - 18:12:04 NZDT

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