.TH "o2cluster" "8" "January 2012" "Version 1.8.7" "OCFS2 Manual Pages"
.SH "NAME"
o2cluster \- Change cluster stack stamped on an \fIOCFS2\fR file system.
.SH "SYNOPSIS"
\fBo2cluster\fR [\fB\-o\fR|\fB\-\-show\-ondisk\fR] [\fB\-r\fR|\fB\-\-show\-running\fR] [\fB\-u\fR|\fB\-\-update\fR[=<clusterstack>]] [\fB\-hvVyn\fR] [device]

.SH "DESCRIPTION"
.PP
\fBo2cluster\fR is used to change the cluster stack stamped on an \fBOCFS2\fR file system.
It also used to list the active cluster stack and the one stamped on-disk. This utility does
not expect the cluster to be online. It only updates the file system if it is reasonably
assured that it is not in-use on any other node. Clean journals implies the file system is
not in-use. This utility aborts if it detects even one dirty journal.

\fIBefore using this utility, the user should use other means to ensure that the volume is
not in-use, and more importantly, not about to be put in-use\fR. While clean journals implies
the file system is not in-use, there is a tiny window after the check and before the update
during which another node could mount the file system using the older cluster stack.

If a dirty journal is detected, it implies one of two scenarios. Either the file system is
mounted on another node, or, the last node to have it mounted, crashed. There is no way, short
of joining the cluster, that the utility can use to differentiate between the two. Considering
this utility is targeted to be used in scenarios when the user is looking to change the
on-disk cluster stack, it becomes a chicken-and-egg problem.

If one were to run into this scenario, the user should manually re-confirm that the file system
is not in-use on another node and then run \fBfsck.ocfs2(8)\fR. It will update the on-disk cluster
stack to the active cluster stack, and, do a complete file system check.

.SH "SPECIFYING CLUSTER STACK
.PP
The cluster stack can be specified in one of two forms. The first as \fBdefault\fR, denoting the
original \fIclassic o2cb\fR cluster stack with local heartbeat. The second as a triplet with the
stack name, the cluster name and the cluster flags separated by commas. Like \fBo2cb,mycluster,global\fR.

The valid stack names are \fBo2cb\fR, \fBpcmk\fR, and \fBcman\fR.

The cluster name can be up to 16 characters. The \fIo2cb\fR stack further restricts the names to
contain only alphanumeric characters.

The valid flags for the \fIo2cb\fR stack are \fBlocal\fR and \fBglobal\fR, denoting the two heartbeat
modes. The only valid flag for the other stacks is \fBnone\fR.

.SH "OPTIONS"
.TP
\fB\-o\fR|\fB\-\-show\-ondisk\fR
Shows the cluster stack stamped on-disk.

.TP
\fB\-r\fR|\fB\-\-show\-running\fR
Shows the active cluster stack.

.TP
\fB\-u\fR|\fB\-\-update\fR[=\fI<clusterstack>\fR]
Updates the on-disk cluster stack with the one provided. If no cluster stack is provided, the
utility detects the active cluster stack and stamps it on-disk.

.TP
\fB\-v, \-\-verbose\fR
Verbose mode.

.TP
\fB\-V, \-\-version\fR
Show version and exit.

.TP
\fB\-y, \-\-yes\fR
Always answer Yes in interactive command line.

.TP
\fB\-n, \-\-no\fR
Always answer No in interactive command line.

.SH "EXAMPLES"

.nf
.ps 9
.ft 6
# o2cluster -r
o2cb,myactivecluster,global

# o2cluster -o /dev/sda1
o2cb,mycluster,global

# o2cluster --update=o2cb,yourcluster,global /dev/sdb1
Changing the clusterstack from o2cb,mycluster,global to o2cb,yourcluster,global. Continue? y
Updated successfully.

.ft
.ps
.fi

.SH "SEE ALSO"
.BR debugfs.ocfs2(8)
.BR fsck.ocfs2(8)
.BR fsck.ocfs2.checks(8)
.BR mkfs.ocfs2(8)
.BR mount.ocfs2(8)
.BR mounted.ocfs2(8)
.BR o2image(8)
.BR o2info(1)
.BR tunefs.ocfs2(8)

.SH "AUTHORS"
Oracle Corporation

.SH "COPYRIGHT"
Copyright \(co 2011, 2012 Oracle. All rights reserved.