VERITAS Volume Manager 3.5 Administrator's Guide (September 2002)

Cluster Initialization and Configuration
256 VERITAS Volume Manager Administrator’s Guide
◆ If the vxconfigd daemon is stopped on the master node, the vxconfigd daemons
on the slavenodes periodicallyattempt torejoin to the master node. Such attempts do
not succeed until the vxconfigd daemon is restarted on the master. In this case, the
vxconfigd daemons on the slave nodes have not lost information about the shared
configuration, so that any displayed configuration information is correct.
◆ If the vxconfigd daemon is stopped on a slave node, the master node takes no
action. When the vxconfigd daemon is restarted on the slave, the slave vxconfigd
daemon attempts to reconnect to the master daemon and to re-acquire the
information about the shared configuration. (Neither the kernel view of the shared
configuration nor access to shared disks is affected.)Until thevxconfigd daemon on
the slavenode has successfully reconnected to thevxconfigd daemon on themaster
node, it hasvery little informationabout the shared configuration andany attempts to
display or modify the shared configuration can fail. For example, shared disk groups
listed using the vxdg list command are marked as disabled; when the rejoin
completes successfully, they are marked as enabled.
◆ If the vxconfigd daemon is stopped on both the master and slave nodes, the slave
nodes do not display accurate configuration information until vxconfigd is
restarted on the master and slave nodes, and the daemons have reconnected.
If the vxclustd daemon determines that the vxconfigd daemon is not running on a
node during a cluster reconfiguration, vxclustd restarts vxconfigd automatically.
Note The -r reset option to vxconfigd restarts the vxconfigd daemon and recreates
all states from scratch. This option cannot be used to restart vxconfigd while a
node is joined to a cluster because it causes cluster information to be discarded.
Node Shutdown
Although it is possible to shut down the cluster on a node by invoking the shutdown
procedure of the node’s clustermonitor, thisprocedureis intendedfor terminating cluster
components after stopping any applications on the node that have access to shared
storage. VxVM supports clean node shutdown, which allows a node to leave the cluster
gracefully when all access to shared volumes has ceased. The host is still operational, but
cluster applications cannot be run on it.
The cluster functionality of VxVM maintains global state information for each volume.
This enables VxVM to determine which volumes need to be recovered when a node
crashes. When a node leaves the cluster due to a crash or by some other means that is not
clean, VxVM determines which volumes may have writes that have not completed and
the master node resynchronizes these volumes. It can use dirty region logging (DRL) or
FastResync if these are active for any of the volumes.