Designing for High Availability in SQL Server: Considerations and Overview

1. SQL Server Special Considerations

2. Overview • SQL Server High Availability • Unicode

3. Lesson: SQL Server High Availability • Designing for High Availability (HA) • Where to Start? • OS options for SQL Server • SQL Server High Availability • Windows Clustering Terminology • Cluster Resource Dependencies • Troubleshooting • SQL Server HA information

4. Designing for High Availability (HA) • HA is about people and processes – technology is just the enabler • Understand the level of HA expected so you can focus • 99.999% 5 minutes per year 98% 7.3 days per year • 99.99% 53 minutes per year 97% 11 days per year • 99.9% 8.8 hours per year 95% 18.3 days per year • 99% 3.6 days per year 90% 36.5 days per year • Identify risks and exposures, and understand tradeoffs • Review all single points of failure • Redundancy is crucial, but don’t forget plans for contingency/disasters

5. Where to Start? • What is the level of HA expected? • Configure enough processing power to handle the workload after a failover. • Use compatible hardware. Entire cluster solution must be in the Windows Catalog or on the former Hardware Compatibility List (HCL). • Use only certified drivers. Crucial for disk devices • Use the right version of the OS • Use the right version of SQL Server • Goal is to have a supported and known configuration • Check for best practices. Look for White Papers on networking, configuration, etc.

6. OS options for SQL Server • Windows 2000 Advanced Server • Max 8 Processors • Max 8 Gb Memory • Windows 2000 Datacenter Server • Max 32 Processors • Max 32 Gb Memory • Windows Server 2003 Enterprise Edition • Max 8 Processors • Max 32 Gb Memory (32-bit) or Max 64 Gb Memory (64-bit) • Windows Server 2003 Datacenter Edition • Min 8 Processors and Max 64 Processors • Max 64 Gb Memory (32-bit) or Max 512 Gb Memory (64-bit)

7. SQL Server High Availability • Failover clustering • Automatic • Great for close distances • Log Shipping • Manual/Scheduled • OK for some levels of HA. • Great for disaster recovery or spanning distances • Native SQL Server Replication • Not an option unless applying schema changes outside of Siebel Tools • Backup and Restore • Always test your backups! • Coordinate with backup/restore of Siebel File System

8. SQL Server 2000 scale out. Federated Server/Cluster Windows Clustering Windows OS server cluster. Not for scale out. (formerly referred to as Active/Passive) Only one SQL Server virtual server concurrently running. (formerly referred to as Active/Active) Up to 16 SQL Server virtual servers per virtual cluster. Single Instance Cluster Multiple Instance Cluster SQL Server 2000 availability clustering built on top of Windows Clustering. Failover Clustering Windows Clustering Terminology

9. Cluster Resource Dependencies • SQL Server resources in a Cluster are dependent on other resources to run • Resources start in a particular order based on defined dependencies • Unless absolutely necessary, do not add resources as dependencies to the SQL Server resources. May cause an outage that has no relation to SQL Server

10. Troubleshooting • Diagnose in this order every time: • Hardware issues • OS issues • Networking issues • Security issues • Windows Server cluster issues • SQL Server issues • Most problems are not related to SQL Server

11. SQL Server HA information • SQL Server 2000 High Availability • 754 pages. • Published by Microsoft Press. • SQL Server 2000 Failover Clustering. http://www.microsoft.com/technet/prodtechnol/sql/2000/maintain/failclus.mspx • Cluster Services in Windows Server 2003. http://www.microsoft.com/technet/prodtechnol/windowsserver2003/technologies/clustering/default.mspx

12. Lesson: Unicode • Unicode Fundamentals and Terminology • Unicode and Localization • Unicode and Siebel • Data Types and Storage

13. Code Page Unicode A coded character set (CCS) meaning an abstract character has been mapped to a non-negative numeric value, usually represented by a hexadecimal value. A standard that attempts to provide a unique number for storing and displaying every character of all the worlds languages, past and present including scientific and technical symbols. Computer systems, e.g. Operating systems (Windows), Databases (SQL, Oracle, DB2) and Applications (Siebel) must decide how they will encode data internally. The Unicode standards introduced a mapping from the set of integers established by the CCS to a set of code units which are integers in binary form represented as actual data inside a computer. The CEF’s have various types of which the most common are the UTF-8, UTF-16 and UCS-2, which is a derivative of UTF-16. Character Encoding Form (CEF) Unicode Fundamentals and Terminology Data in a database is stored as a sequence of bytes (numbers). More Information: http://www.unicode.org/unicode/reports/tr17/

14. Unicode and Localization • Unicode is the storage of the data, whereas Localization is the display/usage of the data • Localization is a set of rules or processes guiding how locale-sensitive data is interpreted when input by a user and how such data is presented to the user. • USA: 10/20/2004 2:30:33 pm • Germany: 2004/10/20 14:30:33

15. Unicode and Siebel • Support for Unicode will depend on your version of the Siebel product and the database* • Siebel on DB2 and SQL Server will support UCS-2 • Siebel Oracle will support UTF-8 • UCS-2 is a fixed length double byte code page • UTF-8 is a variable length single byte code page *Siebel’s support for Unicode on a particular database does not imply that the database only supports that encoding format.

16. Data Types and Storage Language – Encoding Format Chart: It’s important to note where conversions will increase your database size and where there will be no change.

17. Review • SQL Server High Availability • Unicode

18. Microsoft Contacts for More Information • More Information – seblhelp@microsoft.com • Microsoft Contacts: • Anu Chawla – anuchaw@microsoft.com • Frank Mcbath – Frankmcb@microsoft.com