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www.dell.com/powersolutions Reprinted from Dell Power Solutions, August 2006. Copyright © 2006 Dell Inc. All rights reserved. DELL POWER SOLUTIONS 1
CLUSTERING
Data center managers must perform migrations and
upgrades while incurring as little downtime as pos-
sible for mission-critical applications. IT departments
migrating from Novell NetWare—which is being phased
out—to Novell SUSE Linux Enterprise Server face such
a challenge. The Novell Open Enterprise Server (OES)
platform supports both NetWare and Linux, provid-
ing a bridge between these operating systems and an
environment for migration. As OES NetWare systems
are gradually replaced with OES Linux systems, Novell
Cluster Services can help minimize or eliminate down-
time during migration by allowing administrators to
build heterogeneous server clusters comprising both
NetWare and Linux servers. This article describes steps
for configuring Linux nodes and adding them to existing
NetWare clusters as well as considerations for configuring
heterogeneous clusters.
Using Novell Cluster Services
Novell Cluster Services is a multi-node active/active
server-clustering tool that can help improve the avail-
ability, load balancing, and manageability of critical
network resources, including data, applications, and ser-
vices. Novell Cluster Services 1.8, enabled for the Novell
eDirectory™ directory service, is the OES version for
NetWare 6.5 and SUSE Linux Enterprise Server 9. Novell
Cluster Services allows failover, failback, and migration
(load balancing) of individually managed cluster resources.
It supports up to 32 nodes, and any node in the cluster can
restart resources (applications, services, IP addresses, and
volumes) from a failed server in the cluster. All nodes in a
given cluster must be configured with a static IP address,
and they must reside on the same IP subnet and in the same
eDirectory tree.
Novell Cluster Services uses the Split Brain Detec-
tor (SBD) for heartbeat functionality. The SBD monitors
server clusters for nodes that lose their Ethernet connec-
tion but retain all other functionality, a state known as
a split brain. Because this node can no longer reach the
other nodes with Global Interprocess Communication sig-
nals or heartbeats, it tries to take over all of the cluster’s
resources; meanwhile, the other nodes, thinking that the
first node has failed, try to take over its resources. The
SBD stops the smaller side of this split brain or the side
BY CINDY STAP, DEAN OLIVER, AND AHMAD ALI
Managing Live Migrations from Novell NetWare to SUSE Linux Enterprise Server
For many IT departments, avoiding downtime for mission-critical systems during
migrations and upgrades is a top priority. The Novell Cluster Services™ tool can help
manage live cluster migrations from the Novell® NetWare® OS to Novell SUSE® Linux®
Enterprise Server.
Related Categories:
Clustering
Dell PowerEdge servers
Novell eDirectory
Novell NetWare
Novell SUSE Linux
Visit www.dell.com/powersolutions
for the complete category index.
CLUSTERING
DELL POWER SOLUTIONS Reprinted from Dell Power Solutions, August 2006. Copyright © 2006 Dell Inc. All rights reserved. August 20062
not running the master node. In two-node clusters, because both
nodes are the same size and both are running the master node, the
SBD checks for LAN failure and stops whichever node has lost its
network connection. The SBD uses an 8 MB partition on the shared
storage accessible to all nodes in the cluster.
Performing a test migration from NetWare to Linux
In October 2005 a team of Dell engineers configured a test cluster
environment to illustrate the migration path from NetWare to SUSE
Linux Enterprise Server. The test configuration consisted of a three-
node Dell™ PowerEdge™ ™ server cluster running NetWare 6.5 with™
Support Pack 4 and Novell Cluster Services 1.8 (see Figure 1). The
cluster was tied to an eDirectory 8.7.x tree. Each server was config-
ured with dual Gigabit Ethernet1 adapters for LAN connectivity and
QLogic Fibre Channel controllers for storage area network (SAN) con-
nectivity. The cluster also included a Dell/EMC CX600 storage array
with multiple logical units (LUNs). Novell Storage Services™ pools™
were configured on these LUNs as highly available clustered storage
resources and provided highly available file services as Common
Internet File System (CIFS) resources to cluster clients.
Building the Linux nodesIn the test configuration, the first Linux node was built by retir-
ing one of the existing NetWare nodes from the cluster. First,
all of the node’s resources were migrated to the remaining two
NetWare nodes. In addition, the node was removed from the NDS
tree and disconnected from the SAN. Then SUSE Linux Enterprise
Server 9 was installed on this node, and the default OES configura-
tion was selected. After the OS installation, the node was added
back onto the NDS tree.
Novell Storage Services and Novell Cluster Services were added
in the software selection of the YaST (Yet Another Setup Tool) instal-
lation and systems management application. For Linux servers, YaST
includes plug-in utilities for both Novell Storage Services and Novell
Cluster Services. YaST is the main tool for deployment and configu-
ration of Linux nodes in Novell Cluster Services. In OES NetWare,
by contrast, cluster installation, administration, and upgrades are
performed through the Novell Deployment Manager utility, which
runs on a Microsoft® Windows® client.
Configuring Novell Storage Services. To configure Novell
Storage Services, administrators should open YaST and select
System>NSS. They can then authenticate to the tree by entering
the Lightweight Directory Access Protocol (LDAP) server, adminis-
trator, and password information. A unique Novell Storage Services
administrator object name is created.
Configuring Novell Cluster Services. To configure Novell
Cluster Services, administrators should open YaST and select
System>NCS. They can then enter the LDAP server, administra-
tor, and password information. On the next screen, they should
choose “Existing Cluster” and enter the fully distinguished name
(FDN) of the cluster. Because failure can occur at this point if the
Linux server cannot find an existing SBD partition on the SAN, best
practices recommend verifying the partition with the nssmu util-
ity before performing this step. Finally, administrators can use the
Novell iManager console to verify that the Linux server node has
been added to the cluster, as shown in Figures 2 and 3.
Figure 4 lists some of the packages and required services
installed during Novell Cluster Services installation on the Linux
server node.
Configuring heterogeneous cluster environments
After Linux nodes have been added to a NetWare cluster environ-
ment, Novell Cluster Services pushes down various cluster load
and unload scripts, XML files, and .conf files in the /etc/opt/
novell/ncs and/var/opt/novell/ncs directories.
Many of the files contain NetWare-specific commands, which
are translated by the ncs-resourced daemon. For example, the
NetWare command cluster cvsbind add vserver 10.0.0.0 is
translated to the following Linux command:
1 This term does not connote an actual operating speed of 1 Gbps. For high-speed transmission, connection to a Gigabit Ethernet server and network infrastructure is required.
Figure 1. Cluster configuration for test migration from NetWare to Linux
Authentication server
Clients
PowerEdge server PowerEdge server PowerEdge server
Public network Private network
SAN
Dell/EMC CX600storage array
CLUSTERING
www.dell.com/powersolutions Reprinted from Dell Power Solutions, August 2006. Copyright © 2006 Dell Inc. All rights reserved. DELL POWER SOLUTIONS 3
ncpcon bind –ncpservername=vserver
--ipaddress=10.0.0.0
This translation process imposes a restriction on mixed-node
environments: Because NetWare commands can be translated into
Linux commands but not vice versa, cluster resources can be cre-
ated only on NetWare nodes. This restriction becomes irrelevant
once the migration process is complete and all of the Novell Cluster
Services nodes are running Linux.
Administrators also should note the following about mixed-node
cluster environments:
• Online storage reconfiguration is not supported. • NetWare nodes cannot be added using Novell Deployment
Manager. • Resources created on Linux cannot run on NetWare.
Other kernel modules, plug-ins, and paths that would be of
interest for administrators are as follows:
• /opt/novell/ncs • /lib/modules/'uname -r'/ncs/*.ko • /usr/include/ncssdk.h • /usr/lib/libncssdk.so • /proc/ncs • /admin/Novell/Cluster
Novell Cluster Services supports fast-mount journaled file sys-
tems such as Reiser, ext3, and Novell Storage Services. Linux sup-
ports all of these file systems, but NetWare only supports Novell
Storage Services. Therefore, in heterogeneous cluster environments
with Novell Cluster Services, only Novell Storage Services can be
used as the file system for storage resources.
Creating the SBD partitionFor heterogeneous clusters, Novell recommends creating the SBD
partition from NetWare, a task that is usually performed during
cluster creation. In the test configuration, the SBD partition had
already been created from the NetWare node. If necessary, however,
the partition can be created using the following commands:
SBD INSTALL (NetWare)
sbdutil -c -d device_name (Linux)
If the partition is created from Linux, administrators should
enable the NCS:Shared Disk Flag attribute: In iManager, they
should select eDirectory Administration>Modify Object>Cluster
Object>Valued Attributes.
Viewing and configuring heartbeat parametersCluster heartbeat parameters can be viewed and configured in
iManager by selecting Cluster>Cluster Options>Cluster Object>
Properties>Protocols, or from the Linux console by using the
cluster command (see Figure 5).
User space packages Service dependencies
novell-plugin-cluster-services-smp-1.8.0-20050324novell-plugin-cluster-services-3.0.4-5yast2-ncs-2.9.52-0.2
novell-nssadminfsheartbeatpython-ldap
Figure 4. Some packages installed on a Linux server node during Novell Cluster
Services installation Figure 2. Novell iManager Cluster Options screen
Copyright © 2005 Novell, Inc. All rights reserved. Used with permission.
Figure 3. Novell iManager Cluster Manager screen
Copyright © 2005 Novell, Inc. All rights reserved. Used with permission.
CLUSTERING
DELL POWER SOLUTIONS Reprinted from Dell Power Solutions, August 2006. Copyright © 2006 Dell Inc. All rights reserved. August 20064
The following heartbeat parameters can affect failover times:
• QUORUMWAIT: Time in seconds that the cluster waits before
resources start to load • HEARTBEAT: Time in seconds between transmits for all nodes
in the cluster except the master node • TOLERANCE: Time in seconds that the master node gives all
other nodes in the cluster to signal that they are functioning • MASTERWATCHDOG: Time in seconds between transmits for the
master node in the cluster • SLAVEWATCHDOG: Time in seconds that the slave nodes give
the master node in the cluster to signal it is functioning • MAXRETRANSMITS: Maximum number of times transmits can
be attempted between the master node and slave nodes
In the test configuration, the default parameters yielded failover
times of approximately 45 seconds.
Managing storage resourcesThe CIFS protocol for storage resources does not work with Linux
servers. To enable this functionality on Linux nodes in the test
configuration, the Dell test team manually configured a Samba server
to share the cluster volume mount points. These shared mount points
are configured differently by NetWare CIFS and Linux Samba; in the
test configuration, the Samba node was set up to be equivalent to the
existing NetWare CIFS configuration. After manual configuration, the
disk volume was migrated using Novell Cluster Services. An example
stanza in the /etc/samba/smb.conf file is shown in Figure 6.
To bring storage pool objects online, the storage resources pool
must be active and the corresponding volume should be mounted
and active on the master server node. These tasks can be per-
formed using iManager or prompt commands: Entering volumes at a
NetWare prompt or mount at a Linux prompt shows the active vol-
umes on the node. For example, the Linux mount command returns
the information shown in Figure 7.
The admin volume is a virtual volume used in creating and
managing Novell Storage Services volumes. The admin volume is not
persistent; each time the server boots, the volume is re-created.
Entering cat /proc/partitions in Linux shows the avail-
able devices for the node. Novell provides the Enterprise Volume
Management System plug-in evmsgui to allow device, partition,
pool, and volume management. The evmsgui plug-in default loca-
tion is /lib/evms/2.3.3/ncs-1.0.0.so.
Retiring old nodesAll services that are identical across platforms are expected to fail
over from failing NetWare nodes to functioning Linux nodes in a
cluster running Novell Cluster Services 1.8 or later. Services with
identical configuration files and block data formats on both plat-
forms are considered identical across platforms. Apache 2.0.50
and MySQL 4.0.21 can migrate automatically. Services that cannot
automatically fail over require manual migration between server
platforms. Novell Cluster Services enables migration of the storage
volume to the new platform, but configuration files for the service
must be translated and created manually.
Successfully migrating from NetWare to Linux
Novell Cluster Services provides built-in tools and utilities to
help make the migration from NetWare to Linux seamless. Even
in the intermediate heterogeneous stage, the test cluster con-
figuration maintained high availability and industry-acceptable
failover times. Using the rolling migration procedure described
in this article along with manual configuration steps for storage
oes-server02:~ # cluster info protocol
Cluster protocol internals
Heartbeat: 1, Tolerance: 6
Master Watchdog: 1, Slave Watchdog: 8
Max Retransmits: 30
Figure 5. Heartbeat parameters shown using the Linux cluster command
[testvol7]
comment = TESTVOL7
path = /media/nss/TESTVOL7/
writeable = yes
browseable = yes
guest ok = yes
printable = no
Figure 6. Example stanza in the /etc/samba/smb.conf file
/dev/evms/TESTPOOL7 on /opt/novell/nss/mnt/.pools/TESTPOOL7 type nsspool (rw,name=TESTPOOL7)
admin on /admin type nssadmin (rw)
TESTVOL7 on /media/nss/TESTVOL7 type nssvol (rw,name=TESTVOL7)
Figure 7. Active volumes shown using the Linux mount command
CLUSTERING
www.dell.com/powersolutions Reprinted from Dell Power Solutions, August 2006. Copyright © 2006 Dell Inc. All rights reserved. DELL POWER SOLUTIONS 5
resources can help administrators reduce downtime when migrat-
ing server clusters from Novell NetWare to Novell SUSE Linux
Enterprise Server.
Cindy Stap has been in the computing field for 22 years and with Dell for
the past 9 years. She has holds Novell Master Certified NetWare Engineer
(MCNE) and Microsoft Certified Systems Engineer (MCSE) certifications and
has a bachelor’s degree in Computer Science from Almeda University.
Dean Oliver has been a senior analyst in the Dell Linux Operating System
Development Group for five years and holds Novell Certified Linux Engineer
(CLE), Master Certified NetWare Engineer (MCNE), Red Hat Certified Engineer®
(RHCE®), and Microsoft Certified Systems Engineer (MCSE) certifications.
Ahmad Ali is a systems engineer on the Dell Linux Engineering team. He
has a B.S. in Electrical Engineering and an M.S. in Computer Engineering,
both from Florida Atlantic University.
FOR MORE INFORMATION
Novell Cluster Services for NetWare 6.5 online documentation:
www.novell.com/documentation/ncs65/index.html
Novell Cluster Services for Linux online documentation:
www.novell.com/documentation/ncs_lx/index.html
Kosacek, Mike, and Dennis Dadey. “Implementing Novell Cluster
Services.” Dell Power Solutions, Issue 4, 1999.
www.dell.com/content/topics/global.aspx/power/en/
ps4q99_novell
Lang, Richard. “Building a Scalable, Highly Available Novell Cluster
Environment.” Dell Power Solutions, Issue 2, 2000.
www.dell.com/content/topics/global.aspx/power/en/
ps2q00_NetWare
Lang, Richard. “NetWare Cluster Services: Deployment Consider-
ations and Tuning.” Dell Power Solutions, Issue 3, 2000.
www.dell.com/content/topics/global.aspx/power/en/
ps3q00_lang
Pirich, Pete. “Upgrading a Novell NetWare Cluster to Dell SAN
3.0.” Dell Power Solutions, Issue 4, 2000. www.dell.com/
content/topics/global.aspx/power/en/ps4q00_pirich