How to Implement a Cluster of Clusters Atiq Adamjee Senior Architect Novell, Inc. Brad Rupp Software Engineer Novell, Inc.

© March 9, 2004 Novell Inc. 2 one Net: Information without boundaries…where the right people are connected with the right information at the right time to make the right decisions. The one Net vision Novell exteNd ™ Novell Nsure ™ Novell Nterprise ™ Novell Ngage SM : : : :

© March 9, 2004 Novell Inc. 3 The one Net vision Novell Nterprise is an innovative family of products which gives you the power to enable and manage the constant interaction of people with your business systems — regardless of who they are or where they are. Novell Nterprise ™ Novell exteNd ™ Novell Nsure ™ Novell Nterprise ™ Novell Ngage SM : : : :

© March 4, 2004 Novell Inc. 4 Agenda Introductions Assumptions Components of a Disaster Recovery Plan Data Replication Factors Affecting Data Replication Distance Consideration Latency Consideration Bandwidth Consideration Cluster of Clusters Implementation Q & A

© March 4, 2004 Novell Inc. 5 Introductions Atiq Adamjee Senior Architect, Novell Consulting Brad Rupp Software Engineer, Novell Inc.

© March 4, 2004 Novell Inc. 6 Assumptions Knowledge of Novell Cluster Services™ (NCS) Have already implemented NCS or are in the process of implenting NCS Need to implement a disaster recovery plan This is not a full disaster recovery plan – but a large component of it

© March 4, 2004 Novell Inc. 7 Components of a Disaster Recovery Plan A complete disaster recovery plan must include more than just “servers” People Facilities Information Technology Much more...

© March 4, 2004 Novell Inc. 8 Data Replication Data may be replicated in many different ways Host-based Disk-based Asynchronous Synchronous

© March 4, 2004 Novell Inc. 9 Host-based Replication FC WDM SONET ATM IP Etc. Data Center Recovery Site

© March 4, 2004 Novell Inc. 10 Disk-based Replication FC WDM SONET ATM IP Etc. Data Center Recovery Site

© March 4, 2004 Novell Inc. 11 Asynchronous Replication replicate write Latency of I/O to remote disk does not slow down host I/O Data on the remote disk is only as current as the last replication session

© March 4, 2004 Novell Inc. 12 Synchronous Replication (Mirroring) Latency of I/O to remote disk will slow down host I/O Data on the remote disk is always current write 2ms 15ms

© March 4, 2004 Novell Inc. 13 Factors Affecting Data Replication Distance Latency Bandwidth 2 1 3

© March 4, 2004 Novell Inc. 14 Distance Consideration Within a campus Under 10 km Under 100 km Over 100 km

© March 4, 2004 Novell Inc. 15 Distance Consideration Within a campus - use Ethernet or fibre channel Under 10 km – consider fibre channel Under 100 km – fiber, WDM, FC/IP, ATM, SONET, iSCSI, … Over 100 km – iSCSI, fiber, WDM, FC/IP, ATM … As distance increases so does the cost of the connection iSCSI has changed this by allowing SCSI data to be routed over TCP/IP.

© March 4, 2004 Novell Inc. 16 Latency Consideration Shorter round trip delay = more frequent transmission Impacted by overhead, i.e. how much of each packet is really data With longer distances, latency impacts performance more than bandwidth

© March 4, 2004 Novell Inc. 17 Bandwith Consideration What is the amount of daily change in the data? How much time do you have to replicate the data? What is the round trip delay between this site and the distant replica? What is the overhead for the selected transport?

© March 4, 2004 Novell Inc. 18 Cluster of Clusters Powered by NetWare and Novell Cluster Services Manually fails over network services from one cluster to another geographically, separate cluster Provides high availability to your mission critical resources in the event of a disaster SBD and heartbeat issues go away

© March 4, 2004 Novell Inc. 19 Cluster of Clusters Implementation Overview Real World Implementation of a Cluster of Clusters Six servers at the primary site Two servers at the disaster recovery (DR) site EMC CLARiiON SAN at both sites Both SANs mirrored over an OC3 link

© March 4, 2004 Novell Inc. 20 Cluster of Clusters Implementation – Phase I Unmask the LUNs on the SAN so all servers at the site can see all shared devices If using existing NSS pools, mark them as shareable for clustering Install NCS Activate the pools and volumes Create cluster volume objects and virtual servers Configure resources, load/unload scripts, failover priorities, etc. Bring resources online Test failover between servers

© March 4, 2004 Novell Inc. 21 Cluster of Clusters Implementation – Phase II Down the cluster at the primary site Stop SAN mirroring Mask (hide) the LUNs from the servers at the primary site Remove the LUN masking (make the LUNs visible) from the servers at the DR site Repeat the steps in Phase I to set up the DR cluster

© March 4, 2004 Novell Inc. 22 Cluster of Clusters Implementation – Phase III Down the cluster at the DR site Mask (hide) the LUNs from the servers at the DR site Start SAN mirroring Remove the LUN masking (make the LUNs visible) from the servers at the primary site Start the primary cluster

© March 4, 2004 Novell Inc. 23 Cluster of Clusters Implementation – Phase IV Prepare for disaster recovery Login Scripts – create DR scripts ahead of time and comment them out or use tools like the NDS Login Script editor available from Cool Solutions Printing – set up printers at the DR site as printers are location-based entities eDirectory replicas Other services, e.g. DHCP, DNS, SLP, etc.

© March 4, 2004 Novell Inc. 24 Cluster of Clusters Implementation – Phase V Test Cluster Failover Down the cluster at the primary site Stop the SAN mirroring Mask (hide) the LUNs from the servers at the primary site Remove the LUN masking (make the LUNs visible) from the servers at the DR site Enable the cluster (and mount the volumes) at the DR site Make necessary changes to the login scripts Restore other services, e.g. printing, DHCP, DNS, SLP, etc.

© March 4, 2004 Novell Inc. 25 Cluster of Clusters Implementation – Phase VI Test Cluster Failback Down the cluster at the DR site Mask (hide) the LUNs from the servers at the DR site Remove the LUN masking (make the LUNs visible) from the servers at the primary site Enable the cluster (and mount the volumes) at the primary site Make necessary changes to the login scripts Restore other services, e.g. printing, DHCP, DNS, SLP, etc.

Question and Answer

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