NAME

       o2cluster - Change cluster stack stamped on an OCFS2 file system.

SYNOPSIS

       o2cluster  [-o|--show-ondisk]  [-r|--show-running] [-u|--update[=<clusterstack>]] [-hvVyn]
       [device]

DESCRIPTION

       o2cluster is used to change the cluster stack stamped on an OCFS2 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.

       Before 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. 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 fsck.ocfs2(8). It will update the on-
       disk cluster stack to the active cluster stack, and, do a complete file system check.

SPECIFYING CLUSTER STACK

       The cluster stack can be specified in one of two forms. The first as default, denoting the
       original classic o2cb 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
       o2cb,mycluster,global.

       The valid stack names are o2cb, pcmk, and cman.

       The cluster name can be up to 16 characters. The o2cb stack further restricts the names to
       contain only alphanumeric characters.

       The valid flags for the o2cb stack are local and global, denoting the two heartbeat modes.
       The only valid flag for the other stacks is none.

OPTIONS

       -o|--show-ondisk
              Shows the cluster stack stamped on-disk.

       -r|--show-running
              Shows the active cluster stack.

       -u|--update[=<clusterstack>]
              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.

       -v, --verbose
              Verbose mode.

       -V, --version
              Show version and exit.

       -y, --yes
              Always answer Yes in interactive command line.

       -n, --no
              Always answer No in interactive command line.

EXAMPLES

       # 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.

SEE ALSO

       debugfs.ocfs2(8)   fsck.ocfs2(8)   fsck.ocfs2.checks(8)    mkfs.ocfs2(8)    mount.ocfs2(8)
       mounted.ocfs2(8) o2image(8) o2info(1) tunefs.ocfs2(8)

AUTHORS

       Oracle Corporation

COPYRIGHT

       Copyright © 2011, 2012 Oracle. All rights reserved.