By hhnguyen on Mar 21, 2008
In a data-center environment, everybody's goal is to minimize system downtime and maximize the features available in the products they use. That is why every organization is striving to get a high-availability (HA) solution for their applications that are running in a production environment. As every technology evolves day by day, as every product is getting better day by day, every customer-centric organization will strive to create more value to their customers by looking for more innovative features in the software they choose to run their data center, along with better performance and competitive pricing. As such high-value products become available on the market, organizations choose these new and improved products to replace the software products or versions that the data center is currently running on. At the same time, it is a challenging task to upgrade or migrate an existing setup or environment to the latest one with minimal downtime. This is particularly true with the HA solutions that are available in the market.
Be assured that, by having Sun Cluster software as an HA solution for your data center, there is no need to worry about getting the latest version of Sun Cluster in your data center, no matter whether the setup is new or old. The beauty of Sun Cluster software is that it includes multiple methods for upgrading the cluster software, along with the Solaris Operating System and other software in the cluster stack.
The process of upgrading Sun Cluster to the latest version is less complex than one might expect. Some Sun Cluster upgrade methods involve just a single switchover time, the only system downtime the upgrade will require. Without losing any data, without significant downtime, you will be up and running the latest HA solution from Sun Cluster. If you are wondering, is a hassle-free process possible with a minimum downtime, the answer is yes; definitely count on us. We are going to tell you how it is possible.
This article will describe the different upgrade solutions that are available with Sun Cluster 3.2. The individual can choose which particular upgrade method to use, per one's requirements and comfort.
In a rolling upgrade, you upgrade the cluster software to an update release on one or more nodes at a time, depending on the number of nodes and your cluster topology. The cluster services continue on the other nodes except for the time it takes to switch services from the node(s) to be upgraded to the upgraded node(s). The rolling upgrade method is supported only for upgrading minor updates of Sun Cluster software and the Solaris Operating System.
Cluster downtime is limited to the time needed for the cluster to switch services over to an upgraded node.
Dual Partition Upgrade
In a dual-partition upgrade, you divide the cluster into two groups of nodes. You bring down one group of nodes and upgrade those nodes, while the other group of nodes continues to provide services. After you complete the upgrade of the first group of nodes, you switch services to those upgraded nodes. You then upgrade the remaining nodes and boot them back into the cluster to join the rest of the upgraded nodes.
Cluster downtime is limited to the time needed for the cluster to switch services over to the upgraded partition.
Live Upgrade Method
The Live Upgrade method uses the normal Solaris Live Upgrade method. It requires one additional hard disk, which is called the "alternate root" disk. The current root disk continues to host the cluster services until the upgrade operations are successfully completed and committed in the alternate root disk.
A live upgrade maintains your previous cluster configuration until you have upgraded all the nodes and you commit to the upgrade. If the upgraded configuration causes a problem, you can revert to your previous cluster configuration until you can rectify the problem.
Cluster downtime is the single reboot time of the systems.
Standard Upgrade Method
In a standard upgrade method, you shut down the entire cluster before you upgrade the cluster nodes. You return the cluster to the production environment after all nodes are fully upgraded successfully. The cluster will be out of operation until upgrade of Solaris Cluster software, along with the Solaris Operating system if necessary, is completed.
If downtime is not a significant concern, this can be the most efficient method to upgrade a cluster. Use a Cluster Control Panel tool, such as cconsole or cssh, to access all nodes at once and perform the upgrade on all nodes simultaneously from the master console window.
Arun Kurse/Venugopal Ns
Solaris Cluster Engineering