Manage SAS Metadata Server Availability with Hewlett-Packard Technology

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1 Manage SAS Metadata Server Availability with Hewlett-Packard Technology A SAS White Paper

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3 Table of Contents The SAS and Hewlett-Packard (HP) Relationship... 1 Introduction...1 Fault Tolerance of the SAS Metadata Server... 2 Monitoring the SAS Metadata Server... 2 Backing Up the SAS Metadata Server... 3 Conclusion... 3 References...4 i

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5 Manage SAS Metadata Server Availability with Hewlett-Packard Technology The SAS and Hewlett-Packard (HP) Relationship For more than 20 years, HP and SAS have worked together to help customers gain insight into all aspects of their businesses. Together, HP and SAS assist customers in achieving the following benefits: Build a sustainable, competitive advantage. Strengthen and improve shareholder value. Increase future growth and adaptability. Gain maximum return on technology investments. SAS is a premier HP Global Channel Partner, and HP is a preferred ISV partner for SAS Business Intelligence and Analytic applications. SAS continues to be a leading supplier of software solutions under the HP UNIX operating environment. HP's market leadership in high-end servers delivering optimal performance, scalability, and continuous availability provides the perfect platform for the SAS award-winning software solutions. The combination of HP servers and SAS Analytical Intelligence software and SAS Customer Relationship Management Solutions provides unmatched capabilities for customers to turn data into insightful information for addressing today's unique business challenges. Introduction SAS Metadata Server is one of the key technology applications being delivered with SAS 9. The ability to surface metadata from one or more repositories and serve it to applications, via SAS Open Metadata Architecture, enables companies to gather and store data in multiple formats and locations without losing the ability to derive consistent business intelligence from the data. The benefits of metadata are numerous, and the ability of the SAS Metadata Server to provide a centralized and easily managed system for consistent enterprise data repositories means that customers know where their data is located, what it consists of, and how it has been modified. As a result, companies can, quickly and efficiently, get consistent and correct answers for all their strategic business intelligence needs. Because the SAS Metadata Server is key to most SAS 9 applications, you can use the following guidelines to make the SAS Metadata Server more resilient. 1

6 Manage SAS Metadata Server Availability with Hewlett-Packard Technology Fault Tolerance of the SAS Metadata Server The SAS Metadata Server is an in-memory server, which means all queried and updated metadata is held in memory by the server. This results in more RAM than metadata to avoid paging on the server. Each time a SAS application writes information to the SAS Metadata Server, a write command is issued behind the scenes to the back-end metadata that is stored on disk. A sync command is issued to force the file buffers to be written to disk. Because the SAS Metadata Server relies heavily on this back-end metadata, it is essential that the location where the back-end metadata is written is as fault-tolerant as possible. There are two ways to do this. The first way is to ensure that the file system where the back-end data is written is always available, for example, with a RAID 0+1 file system. The second way is to use a thirdparty tool to ensure that the computer stays available, that is, that the processing power, memory, and disks are available. Designing a highly available, fault-tolerant system requires that the system s single points of failure are minimized or completely eliminated. The HP MC/ServiceGuard architecture minimizes application downtime by supporting a quick application switchover to a redundant server in the event of a failure. Because HP experience shows that unplanned downtime for a system comes from multiple sources, it is important to have a comprehensive approach for high availability. This approach should include hardware and software faults, environmental aspects, and human factors. HP has designed multiple approaches to highly available servers and services based on business needs and demands. Monitoring the SAS Metadata Server To ensure that the SAS Metadata Server is always running, you can use a third-party monitoring tool, such as HP OpenView, to ensure that the server has a heartbeat. If HP OpenView does not find a heartbeat, options are provided. For example, HP OpenView can re-start the SAS Metadata Server, provide an interface that guides the operator through a correct re-start process, or page someone from IT to look at the problem. HP OpenView Operations provides a single-pane-of-glass view for close and efficient control of events that are happening across all systems in your environment. This creates a Mission Control center for your entire distributed environment. From the HP OpenView Operations console, messages, alarms, PCs, workstations, and servers are monitored and managed by an IT operator. In the SAS environment, servers such as the SAS Metadata Server can be monitored for status (up or down) and transactional capability. In addition, all HP OpenView Operations events are logged for auditing and review purposes. 2

7 Manage SAS Metadata Server Availability with Hewlett-Packard Technology Backing Up the SAS Metadata Server The SAS Metadata Server should be backed up from time-to-time. To perform a backup, put the SAS Metadata Repository into read-only mode, stop execution to the server, or shut the server down. While the SAS Metadata Server is stopped for writes, use the SAS Metadata Server backup utility to copy to another location the SAS Metadata Repository that has been flushed to disk, or back up the repository with your usual backup system. Preparing the SAS Metadata Server for a backup might cause your SAS applications to become disabled, especially, the applications that require write access to the SAS Metadata Server. If your SAS application needs to be available at all times, you should use a tool that can quickly back up the SAS Metadata Repository that has been flushed to disk. HP VxFS provides a mechanism for taking snapshot images of mounted file systems, which is useful for making backups. The snapshot file system is an exact image of the original file system, which is called the snapped file system. The snapshot is a consistent view of the original file system at the time that the snapshot is made. Selected files can be backed up from the snapshot by using the cpio or cp command), or the entire file system can be backed up by using the vxdump or fscat commands). By creating a file system that contains only the SAS Metadata Server backup files, you can quickly take a snapshot of this file system for archiving while maintaining the maximum uptime for the SAS Metadata Server. The mount command is used to create a snapshot file system; there is no mkfs command involved. A snapshot file system is read-only, and it exists as long as it and the snapped file system are mounted. A snapped file system cannot be unmounted until after any corresponding snapshots are unmounted. A snapshot file system ceases to exist when unmounted. While it is possible to take multiple snapshots of a file system at different times, it is not possible to make a snapshot of a snapshot. Conclusion The SAS Metadata Server provides a foundation for greater metadata sharing to support more advanced and lucrative analytical intelligence. Metadata usage is consistent and accurate for analysis, resulting in reduced errors in decision-making for your report consumers. The SAS Metadata Server provides one version of the facts, and lets you interpret the results in the same way and spend less resources analyzing and interpreting data from disparate locations. These guidelines will help you keep the SAS Metadata Server available for your SAS applications. 3

8 Manage SAS Metadata Server Availability with Hewlett-Packard Technology References SAS 9.1 Open Metadata Architecture: Best Practices Guide VERITAS FlashSnap Software HP High availability technology HP OpenView operations for UNIX HP JFS 3.3 and HP OnLineJFS 3.3 VERITAS File System 3.3 System Administrator's Guide 4

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10 World Headquarters and SAS Americas SAS Campus Drive Cary, NC USA Tel: (919) Fax: (919) U.S. & Canada sales: (800) SAS International PO Box Neuenheimer Landstr D Heidelberg, Germany Tel: (49) Fax: (49) SAS and all other SAS Institute Inc. product or service names are registered trademarks or trademarks of SAS Institute Inc. in the USA and other countries. indicates USA registration. Other brand and product names are trademarks of their respective companies. Copyright 2002, SAS Institute Inc. All rights reserved US.0804