Making Domino
Clusters a Key Part of
Your Enterprise
Disaster Recovery
Architecture
Andy Pedisich
Technotics
© 2011 Wellesley Information Services. All rights reserved.
In This Session …
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Clustering is one of my favorite Domino features
 Introduced with Release 4.5 in December of 1996
 We have seen an increased adoption in clustering Domino
servers over the past two years
 Much of that was for disaster recovery
Some enterprises have been using Domino clustering for disaster
recovery for years
 This session shares as much information as possible about the
topic based on what I’ve seen, heard about, and discovered
creating Domino-based disaster recovery solutions
 And most importantly, the session speaks to the all important
issues about managing failovers
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What We’ll Cover …
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Convincing management that DR clusters rock
Exploring the choices for a clustered DR architecture
Mastering cluster replication
Setting up a private LAN for cluster traffic
Managing cluster failover and load balancing
Understanding the role of iNotes in your DR solution
Reviewing the 7 important rules for configuring DR clusters
Wrap-up
2
Setting a Baseline for Concepts
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First, lets make sure that everyone knows when you see the
letters DR, we’re talking about disaster recovery
Disaster recovery is part of a larger concept referred to as
business continuity
 That’s what we plan to do to keep our businesses running while
disruptive events occur
 These events could be extremely local, like a power outage in
a building
 Or they could be regional, like an earthquake or tornado, or a
disaster caused by humans doing their thing
Disaster recovery has its focus on the technology that supports
business operations
3
Why Use Domino for Disaster Recovery
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Domino clustering has been accepted by many organizations as
an important part of their DR infrastructure
 Although that’s not a total endorsement as corporations do
wacky things
Clustering works with just about all things Lotus Notes/Domino
such as
 Email, calendaring, Traveler, BlackBerry, and roaming user
Clustering is included as part of your enterprise server licenses
 Clusters clearly should be exploited in every enterprise
 And they should have a solid role in any DR solution for
messaging and collaboration
4
Important Facts to Help You Sell Clustering for DR
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Here are some facts to back you up when you start making plans
to use Domino clusters for DR
 Clustering is a shrink wrapped solution
 It’s not new. As a matter of fact, it’s been burned in for years.
 It works really well
 It’s automatic
 It’s easy to set up and maintain
 It’s easy to test
The biggest drawback for most companies using clusters is the
increase in storage requirements since their data size is double
 Domino Attachment and Object Services (DAOS) can
reduce that size by 30% to 40%
5
What We’ll Cover …
•
•
•
•
•
•
•
•
Convincing management that DR clusters rock
Exploring the choices for a clustered DR architecture
Mastering cluster replication
Setting up a private LAN for cluster traffic
Managing cluster failover and load balancing
Understanding the role of iNotes in your DR solution
Reviewing the 7 important rules for configuring DR clusters
Wrap-up
6
Basic Clustering Requirements
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All servers in the cluster must:
 Run on Domino Enterprise or Domino Utility server
 Be connected using high-speed local area network (LAN) or a
high-speed wide area network (WAN)
 Use TCP/IP and be on the same Notes named network
 Be in the same Domino domain
 Share a common Domino directory
 Have plenty of CPU power and memory
 It’s safe to say that clustered servers need more power and
more disk resources than unclustered servers
A server can be a member of only one cluster at a time
7
Technical Considerations for Disaster Recovery Clusters
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A few guidelines regarding configuring clusters, especially for
clusters used for disaster recovery
 Servers in a cluster should not use the same power source
 Nor should they use the same network subnet or routers
 They should not use the same disk storage array
 They should not be in the same building
Your clustered DR solution should ideally be in different cities
 Never in the same room
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Keep Your Distance
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Good DR cluster designs should take into account both local and
regional problems
Consider a financial company who had clustered servers in two
separate buildings across the street from each other in Manhattan
 This firm now has primary servers in offices in New York City
 And failover servers are thousands of miles away
Another firm has primary servers in Chicago
 With a failover server in the UK
A college has primary and failover servers separated by 200 miles
Another company we know is just starting out with DR and has
servers 25 miles from each other
 A good start, but they really want more distance
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Servers Accessed Over a Wide Area Network
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If servers are as far away as they are supposed to be, there might
be some latency in the synchronization of the data
 If this is the case, users might not find the failover server is up
to date with their primary server during a failover
Everyone must be aware that this is a possibility
 Expectations must be set
 Or management needs to provide budgets for better
networking
Work out all of these details in advance with management
 Get them written down and approved so there are no surprises
10
Most Common DR Cluster Configuration
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The most common DR cluster configuration is active/passive
 Servers on site are active
 Servers at the failover site are passive, waiting for failover
 Sometimes domains use this failover server as a place to do
backups or journaling
 The number of servers in the cluster usually vary
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There could be 1 active and 1 passive
Or 2 or 3 active and 1 passive
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The Active/Passive Clustered Servers
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Active/Passive servers
 Cluster has two servers: one active, the other not generally
used or used for backing up
 Very common disaster recovery setup
Each server holds replicas of all the files from the other server
 During failover all users flip to the other server
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The 3 Server Cluster for DR
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Three or more servers in the cluster
 There are two replicas for each cluster supported application or
mail file
Each primary server holds the mail files of the users assigned to
that server
 Replicas of mail file from both primary servers are on the
failover
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3 Server Cluster with One Primary Server Down
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If a primary server goes down, users from that server go to the
failover server
 Easy to understand, and you save yourself a server
 You’ll still need twice the total disk space of Mail1 and Mail2
 What happens when both Mail1 and Mail2 are unavailable
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Both Primary Servers Are Down
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If both primary servers are down, the last server in the cluster has
to support everyone
 Remember that generally speaking only about 60% to 70% of
users assigned to a server are on there concurrently
 Still that has to be a pretty strong server with fast disks
Some sites have remote servers as primary and failover happens
at the home office data center
15
What We’ll Cover …
•
•
•
•
•
•
•
•
Convincing management that DR clusters rock
Exploring the choices for a clustered DR architecture
Mastering cluster replication
Setting up a private LAN for cluster traffic
Managing cluster failover and load balancing
Understanding the role of iNotes in your DR solution
Reviewing the 7 important rules for configuring DR clusters
Wrap-up
16
Understanding Cluster Replication
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Cluster replication is event driven
 It doesn’t run on a schedule
 The cluster replicator detects a change in a database
and immediately pushes the change to other replicas
in the cluster
If a server is down or there is significant network latency, the
cluster replicator stores changes in memory so it can push them
out when it can
 If a change to the same application happens before a previous
change has been sent, the CLREPL gathers them and sends
them all together
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Streaming Cluster Replication
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R8 introduced Streaming Cluster Replication (SCR)
 This newer functionality reduces replicator overhead
 Provides reduction in cluster replicator latency
As changes occur to databases, they are captured and
immediately queued to other replicas in the same cluster
 This makes cluster replication more efficient
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SCR Only Works with R8
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If one server in the cluster is R8 another is not, Domino will
attempt SCR first
 When that doesn’t work, it will fall back on standard cluster
replication
If you’d like to turn off SCR entirely to ensure compatibility, use
this parameter
 DEBUG_SCR_DISABLED=1
 This must be used on all cluster mates
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Only One Cluster Replicator by Default
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When a cluster is created, each server has only a single cluster
replicator instance
 If there have been a significant number of changes to many
applications, a single cluster replicator can fall behind
 Databases synchronization won’t be up to date
If a server fails when database synch has fallen behind, users will
think their mail file or app is “missing data”
 They won’t understand why all the meetings they made this
morning are not there
 They think their information is gone forever!
 Users need their cluster insurance!
20
Condition Is Completely Manageable
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Adding a cluster replicator will help fix this problem
You can load cluster replicators manually using the following
console command
 Load CLREPL
 Note that a manually loaded cluster replicator will not be
there if the server is restarted after manually loading a
cluster replicator
Add cluster replicators permanently to a server
 Use this parameter in the NOTES.INI
 CLUSTER_REPLICATORS=#
I always use at least two cluster replicators
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When to Add Cluster Replicators
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But how do you tell if there’s a potential problem?
 Do you let it fail and then wait for the phone to ring?
 No!
You look at the cluster stats and get the data you need to make an
intelligent decision
 Adding too many will have a negative effect on server
performance
Here are some important statistics to watch
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Key Stats for Vital Information About Cluster Replication
Statistic
What It Tells You
Acceptable values
Replica.Cluster.
SecondsOnQueue
Total seconds that last DB
replicated spent on work queue
< 15 sec – light load
< 30 sec – heavy
Replica.Cluster.
SecondsOnQueue.Avg
Average seconds a DB spent on Use for trending
work queue
Replica.Cluster.
SecondsOnQueue.Max
Maximum seconds a DB spent
on work queue
Use for trending
Replica.Cluster.
WorkQueueDepth
Current number of databases
awaiting cluster replication
Usually zero
Replica.Cluster.
WorkQueueDepth.Avg
Average work queue depth
since the server started
Use for trending
Replica.Cluster.
WorkQueueDepth.Max
Maximum work queue depth
since the server started
Use for trending
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What to Do About Stats Over the Limit
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Acceptable Replica.Cluster.SecondsOnQueue
 Queue is checked every 15 seconds, so under light load,
should be less than 15
 Under heavy load, if the number is larger than 30, another
cluster replicator should be added
If the above statistic is low and Replica.Cluster.WorkQueueDepth
is constantly higher than 10 …
 Perhaps your network bandwidth is too low
 Consider setting up a private LAN for cluster
replication traffic
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Stats That Have Meaning but Have Gone Missing
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There aren’t any views in Lotus version of Statrep that let you see
these important statistics
 Matter of fact, the Cluster view is pretty worthless
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The Documents Have More Information
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The cluster documents have much better information
 You can actually use the data in the docs
 But they still lack key stats, though they’re in each doc
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Stats That Have Meaning but Have Gone Missing
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But there is a view like that in the Technotics R8.5 Statrep.NTF
 It shows the key stats you need
 To help track and adjust your clusters
 It is included on the CD for this conference
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My Column Additions to Statrep
Column Title
Formula
Formatting
Min on Q
Replica.Cluster.SecondsOnQueue / 60
Fixed (One
Decimal Place)
Min/Q Av
Replica.Cluster.SecondsOnQueue.Avg / 60
Fixed (One
Decimal Place)
Min/Q Mx
Replica.Cluster.SecondsOnQueue.Max / 60
Fixed (One
Decimal Place)
WkrDpth
Replica.Cluster.WorkQueueDepth
General
WD Av
Replica.Cluster.WorkQueueDepth.Avg
General
WD Mx
Replica.Cluster.WorkQueueDepth.Max
General
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Use a Scheduled Connection Document Also
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Back up your clustered replication with a scheduled connection
document between servers
 Have it replicate at least once per hour
 You’ll always be assured to have your servers in sync even if
one has been down for a few days
 And it replicates deletion stubs too!
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What We’ll Cover …
•
•
•
•
•
•
•
•
Convincing management that DR clusters rock
Exploring the choices for a clustered DR architecture
Mastering cluster replication
Setting up a private LAN for cluster traffic
Managing cluster failover and load balancing
Understanding the role of iNotes in your DR solution
Reviewing the 7 important rules for configuring DR clusters
Wrap-up
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Busy Clusters Might Require a Private LAN
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A private LAN separates the network traffic the cluster creates for
replication and server probes
 And will probably leave more room on your primary LAN
Start by installing an additional network interface card (NIC) for
each server in the cluster
 Connect the NICs through a private hub or switch
31
Setting Up the Private LAN
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Assign second IP address to additional NIC
Assign host names to the addresses in the local HOSTS file on
each server
 Using DNS is a best practice
 10.200.100.1 mail1_clu.domlab.com
 10.200.100.2 mail2_clu.domlab.com
 Test by pinging the new hosts from each server
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Modify Server Document
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For each server in the cluster, edit the server document to enable
the new port
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Set Parameters so Servers Use Private LAN
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Make your clusters use the private LAN for cluster traffic by
establishing the ports in the server NOTES.INI with these
parameters
 CLUSTER=TCP,0,15,0
 PORTS=TCPIP,CLUSTER
 CLUSTER_TCPIPADDRESS=0,10.200.100.2:1352
 You will use the address of your NIC card
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Parameters to Make the Cluster Use the Port
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Use the following parameter to ensure Domino uses the port for
cluster traffic
 SERVER_CLUSTER_DEFAULT_PORT=CLUSTER
Use this parameter just in case the CLUSTER port you’ve
configured isn’t available
 SERVER_CLUSTER_AUXILIARY_PORTS=*
 This allows clustering to use any port if the one you’ve
defined isn’t available
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Keep Users Off the Private LAN
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To keep users from grabbing on to the private LAN port, take the
following steps
 Create a group called ClusterServers
 Add the servers in the cluster to this group
Add the following parameter to the NOTES.INI of both servers
 It will keep users from connecting through the CLUSTER port
 Allow_Access_Cluster=ClusterServers
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What We’ll Cover …
•
•
•
•
•
•
•
•
Convincing management that DR clusters rock
Exploring the choices for a clustered DR architecture
Mastering cluster replication
Setting up a private LAN for cluster traffic
Managing cluster failover and load balancing
Understanding the role of iNotes in your DR solution
Reviewing the 7 important rules for configuring DR clusters
Wrap-up
37
Respect the Users
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Clustering provides outstanding service levels for users
 But the process of failing over is sometimes hard on users
 Failover is actually the most difficult moment for users
And sometimes errors in network configuration might prevent
successful failover
 For example, the common name of the server should be listed
as an alias in DNS to ensure users can easily open their
application on the servers
 If the server is not in DNS, the clients won’t know how to get
to the failover servers
38
Best Practice for Cluster Management
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Best Practice:
 Don’t take a clustered server down during working hours
unless it is absolutely necessary
 A non-planned server outage, such as a crash or power
failure, is a legitimate reason to fail over
Resist the urge to take a server down because you know it’s
clustered
 You could probably do it, but the risk of a hard failover will
probably cause unwanted help desk calls
39
Easiest Cluster Configuration to Manage
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The Active/Passive model of clustering is by far the easiest to
manage
Use parameters in the NOTES.INI file on the servers in the cluster
that allow users on the primary one server
 But don’t allow them on the failover server
40
Check for Server Availability
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The parameters we use are thresholds that check the cluster
statistic Server.AvailabilityIndex (SAI)
 This statistic shows how busy the server is
 100 means it’s not busy at all
 0 means it’s crazy busy
41
Adjusting the Threshold
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Setting the parameter Server_availablity_threshold controls
whether users can access the server
 50 means if the SAI is above 50, then failover users to another
server
 A setting like this can be used for load balancing
 100 means the SAI must be 100, which means the server must
be 100% available
 This translates into “nobody is allowed on the server”
 0 means that load balancing and checking the SAI is turned off
These thresholds can come in handy
42
Setting Up Active/Passive Servers in a Cluster
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Let’s look at the following scenario
 Mail1 is the active primary; Mail2 is the passive failover
To allow users to access their primary server, use this parameter
in the NOTES.INI of Mail1
 Server_availablity_threshold = 0
 Use this console command:
 Set config server_availability_threshold=0
Prevent users from accessing failover server Mail2; use this
parameter
 Server_availablity_threshold = 100
 Use this console command:
 Set config server_availability_threshold=100
Administrators will still be able to access this server
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Mail1 Is Crashing
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If Mail1 crashes, the Notes client will disregard our setting of 100
on Mail2 and users will be permitted
To help stabilize the system use this parameter on Mail2
 Server_availability_threshold = 0
 Let all users aboard
While Mail1 is down, enter this parameter into the NOTES.INI to
prevent users from connecting:
 Server_restricted=2
 2 will keep the setting after a server restart
 Setting it to 1 also keeps them off, but the setting will be
disabled with a 0 after restarting the server
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Recovering After a Crash
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When Mail1 is brought back up after the crash, no one will be
permitted to access it except administrators
 That’s because of the Server_restricted=2 setting
 Leave it that way until the end of the day
The ugliest part about failing over is the client part
 Clients are working just fine on Mail2
 By the way, iMap and POP3 users still have access to Mail1
At the day’s end, switch the Server_availability_threshold back to
100 on Mail2 and 0 on Mail1
Issue this console command on Mail2
 Drop all
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Taking a Clustered Server Down Voluntarily
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If you must take clustered Mail1 server down, set
Server_restricted=2, then drop all at the console
 Remember that POP3 and iMap users won’t like you very much
Set Mail2 to Server_availability_threshold to 0
Don’t forget to set the Server_Restricted back to 0 when the crisis
has passed
 I know someone who forgot to do this a couple of times
 This person could access the server and work because he
was in an administrator’s group
 However nobody else could get on the server and he made
all the users very angry
46
Triggering Failover
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You can set the maximum number of concurrent NRPC users
allowed to connect to a server
 Server_MaxUsers NOTES.INI variable
 Set variable to a number determined in planning stage
Set variable using console command
 Or use NOTES.INI tab in server configuration document
 Set config Server_MaxUsers = desired maximum number of
active concurrent users
 Additional users will fail over to the other members of
the cluster
47
Load Balancing
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If you’d like to load balance your servers, determine what your
comfort range is for how busy your servers are and set the
Server_availablity_threshold accordingly
 Perhaps start with a value of 60
 Users should fail over when the SAI goes below 60
Pay close attention to the SAI in the STATREP.NSF, which is
listed under the Av Inx column
 Some hardware can produce inaccurate SAI reading and cause
users to failover when it’s not necessary
48
SAI Is Unreliable in Some Cases
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Note how in this case, the Server Availability Index never seems
to get much above 50 consistently
 Users would be failing over constantly
 And if both servers had the issue, users would be bouncing
back and forth between the clustered servers
49
The Expansion Factor
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Cluster members determine their workload based on the
expansion factor
 This is calculated based on response times for recent requests
 Server compares recent response time to minimum response
time that the server has completed
 Example: Server currently averages 12ms for DBOpen
requests; minimum time was 4ms
 Expansion factor = 3 (current time/fastest time)
 This is averaged over different types of transactions
 Fastest time is stored in memory and in LOADMON.NCF
 LOADMON.NCF is read each time server starts
50
The Expansion Factor (cont.)
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But sometimes Domino has a difficult time calculating the
expansion factor
 The result is that the Server_AvailabilityIndex is not a reliable
measure of how busy the server is
 This can happen with extremely high performing servers
If you see a very low Server_AvailabilityIndex at a time you know
servers are supposed to be idle and you are trying to load
balance, there is something you can do to correct it
 And Domino can help!
51
Changing Expansion Factor Calculation
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Use this parameter to change how the Expansion Factor is
calculated
 SERVER_TRANSINFO_RANGE=n
To determine the optimal value for this variable:
 After the server has experienced heavy usage use this console
command:
 Show AI
 This means, show the availability index calculation

It has nothing to do with that 2001 Steven Spielberg movie about the
robot that looks like a child and tries to become a real boy
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An Easy Way to Find the Parameter Value
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Show AI is a console command that has been around since
Domino Release 6
 It runs some computations on the server
 And suggests a SERVER_TRANSINFO_RANGE for you
53
Events to Monitor When Using Clusters
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Use event monitoring to look for certain problems that could ruin
your clustering by preventing replication
 Look for the following phrases
 “cannot replicate database”
 “folder is larger than supported”
 They both mean that users are going to hate you in the
event of a failover

Because their databases will not be in synch
54
Disaster Recovery Is a Special Case
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Many enterprises configure their clusters for manual failover
 They don’t want the user to fail over unless they permit it
To keep users off of the failover servers, use the following
parameters in the NOTES.INI of the server
 Server_restricted=2
 This will keep off all users until you set it to a zero
 Server_availability_threshold=100
 The server looks busy and keeps everyone on the primary
 Set it to zero to allow users on the server
 Keep in mind, if the primary servers are down, the users
won’t have a server to work on unless you manually reset
these parameters
55
What We’ll Cover …
•
•
•
•
•
•
•
•
Convincing management that DR clusters rock
Exploring the choices for a clustered DR architecture
Mastering cluster replication
Setting up a private LAN for cluster traffic
Managing cluster failover and load balancing
Understanding the role of iNotes in your DR solution
Reviewing the 7 important rules for configuring DR clusters
Wrap-up
56
Things That Do Not Cluster with Domino Clustering
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Only traffic over NRPC port 1352 will fail over
Other TCP/IP services will not fail over, including:
 IMAP
 POP3
 HTTP
This means iNotes users will not fail over
 But that doesn’t mean you can’t make it work
 In the aftermath of Katrina, some companies found that
browser-based email was a savior
57
High Availability Is Not Disaster Recovery
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IBM/Lotus has several recommendations for achieving high
availability with iNotes
For example, Internet Cluster Manager
 This can redirect the initial URL for an application to one of
several back-end mail servers
 However, if the mail server becomes unavailable after a
session is started, there is a way to recover and switch to
another server that has a replica of the mail file
IBM/Lotus also recommends an HTTP load balancer to help with
high availability, and with DR to a certain extent
 The issue is, what happens when the load balancer is
unavailable?
58
iNotes Users Accessing a Hub Server
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The IWAREDIR.NSF is an application that helps direct browser
requests to a user’s mail server
 Any user on either server Mail1 or Mail2 connects to either
iNotes server that is deployed using the IWAREDIR.NSF
 The IWAREDIR.NSF looks up their name in the Domino
directory and “redirects” them to their mail server
 But it is not designed to take them to a failover server
However, it is possible to have a second version of this file with
code changes that will take a user to their failover mail server
59
Open the IWAREDIR.NSF Using the Designer Client
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Open the AutoLogin form using the Notes Designer Client
 At the very bottom, you’ll find a field called $$HTMLHead
 This contains the code that discovers the user’s mail server
and mail file name
60
Section of Code That Can Be Modified
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In this field is code that can be modified to point the user to the
failover server rather than to their primary mail server
 There’s a link at the end of this presentation to some extreme
programming you can do with this field
61
Code to Point Users to Failover Server
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If the address book says the user’s mail is on Mail1, but you want
to take them to server Mail1F, the failover box, the code can be
changed to something like this
 This is an @if statement that essentially says, if the directory
states that the MailServer for the user is Mail1, take them to
Mail1F, the failover server
 This failover version of the IWAREDIR.NSF that could be
called IWAREDIRF.NSF
62
During Normal Operation
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During a normal day with no need for failover, the IWAREDIR.NSF
would be specified as the home URL for the server
 Users would be taken to their home servers and their mail files
automatically
63
During a Failover Situation
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When required, this configuration can be changed to use the
failover version, the IWAREDIRF.NSF
 After this change is made, HTTP must be restarted
64
Restarting the HTTP Task
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Although the HTTP task can be restarted, the most reliable
method is to shut down HTTP and load it again
From the Domino console use these commands
 Tell HTTP quit
 Load HTTP
65
iNotes Is There When You Need It
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When there are no fat Notes clients, iNotes can have extreme
value and maintain communications in your organization
 It’s worth planning it out so that when users call the help desk
during an emergency they can point the users to any DR server
that is configured to use the IWAREDIRF.NSF
 That’s the failover version of your redirector
66
What We’ll Cover …
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•
•
•
•
•
•
•
Convincing management that DR clusters rock
Exploring the choices for a clustered DR architecture
Mastering cluster replication
Setting up a private LAN for cluster traffic
Managing cluster failover and load balancing
Understanding the role of iNotes in your DR solution
Reviewing the 7 important rules for configuring DR clusters
Wrap-up
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7 Rules for Clustering Domino Servers for Disaster
Recovery
1.
2.
3.
4.
5.
6.
7.
Get agreement from all parties before you start configuring
Be sure everyone agrees on what failover means and what kind of
disaster you are preparing for, such as local or regional outages
Keep primary and failover servers as far apart as possible
Actually test the failover scenarios so that there is no doubt that
the configuration works
Consider manual failover to prevent users from accessing servers
over a wide area network or slow connections
Review cluster statistics regularly to ensure there are enough
cluster replicators
Review the CLUDBDIR.NSF to make sure there is a failover replica
for each database on the primary server
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What We’ll Cover …
•
•
•
•
•
•
•
•
Convincing management that DR clusters rock
Exploring the choices for a clustered DR architecture
Mastering cluster replication
Setting up a private LAN for cluster traffic
Managing cluster failover and load balancing
Understanding the role of iNotes in your DR solution
Reviewing the 7 important rules for configuring DR clusters
Wrap-up
69
Resources
•
•
•
Achieving high availability with IBM Lotus iNotes
 www10.lotus.com/ldd/dominowiki.nsf/dx/Achieving_high_availability
_with_IBM_Lotus_iNotes
ServersLookup Form for IWAReder to return User replicas for
Load Balancers and Reverse Proxies to use
 www10.lotus.com/ldd/dominowiki.nsf/dx/ServersLookup_Form_for_I
WAReder_to_return_User_replicas_for_Load_Balancers_and_R
everse_Proxies_to_use
Understanding IBM Lotus Domino server clustering
 www.ibm.com/developerworks/lotus/documentation/d-lsdominoclustering/index.html
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Resources (cont.)
•
How to test cluster failover on one Domino database (application)
 www304.ibm.com/support/docview.wss?rs=899&uid=swg21280021
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7 Key Points to Take Home
•
•
•
•
Disaster recovery is part of the bigger concept known as business
continuity
The biggest drawback when using DR clusters is disk space
consumption, which can be decreased by implementing Domino
Attachment and Object Service
A three-server cluster, with two primary servers and one failover
they share, is an excellent way to conserve server resources and
licensing costs
Make sure your clustered servers are configured with scheduled
connection documents because deletion stubs don’t replicate via
cluster replication
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7 Key Points to Take Home (cont.)
•
•
•
Use the Allow_Access_Portname parameter to prevent users from
accidently using the private LAN between clustered servers
Failing over is the hardest part for users
iNotes is an excellent way to keep users connected during a
disaster
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Your Turn!
How to contact me:
Andy Pedisich
Andyp@technotics.com
HTTP://www.andypedisich.com
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