Free Passive Support
SQL Server is the only Product that has an extended fail-over rights actually provided in the PUR, as below, this means you can set up a separate server in passive mode to take the duties of the active SQL server if it should fail, this support is provided on a temporary basis, for a max of 30days
SQL Server 2005 offers 3 types of fail-over support:
Database mirroring is a new SQL Server 2005 technology for increasing database availability. Database mirroring transfers transaction log records directly from one server to another and can quickly fail-over to the standby server.
Fail-over clustering. Fail-over clustering is a process in which the operating system and SQL Server 2005 work together to provide availability in the event of an application failure, hardware failure, or operating-system error. Fail-over clustering provides hardware redundancy through a configuration in which mission-critical resources are transferred from a failing machine to an equally configured server automatically.
Back-up Log-Shipping. Log-shipping increases a SQL Server database’s availability by automatically copying and restoring the database’s transaction logs to another database on a standby server. Because the standby database receives all changes to the original database, it’s an exact duplicate of the original database—out of date only by the delay in the copy-and-load process. You then have the ability to make the standby server a new primary server if the original primary server becomes unavailable. When the original primary server becomes available again, you can make it a new standby server—effectively reversing the servers’ roles.
The purpose of the passive server is to absorb the data and information held in another server that fails.
Database Mirroring and Fail-Over Clustering will be available for Standard and Enterprise Editions.
Back-Up Log Shipping will be available in Workgroup, Standard and Enterprise Editions.
Figure 3. Passive Servers. The passive server does not require a license given that no queries are being executed against it.
Figure 4. Passive Servers. The passive server requires a license, given that queries are being run against snapshot reporting.
SQL permits Multi-Instancing
Were multiple copies of an application run concurrently on a single copy of an OS.
Multi-instancing for SQL Server 2005 can take place both in a virtual environment or in a physical environment.
While multi-instancing offers a relatively high degree of isolation between copies of SQL2005, this isolation takes place at the application level (instead of at the OS level).
When SQL Server 2005 runs inside a virtual operating environment, it requires at least one license per virtual operating environment.
Several copies or instances of SQL Server 2005 can run inside a virtual operating environment.
These must be licensed as follows:
When licensed Server / CAL
Workgroup, Standard and Enterprise Editions now allow for unlimited instances within each virtual or physical operating environment. Previously, only the Enterprise Edition of the Server license allowed multi-instancing. Each virtual of physical operating environment containing a running instance of SQL requires a Server license.
When licensed Per Processor
Workgroup, Standard and Enterprise Editions allow for unlimited instances in each virtual or physical operating environment. Each virtual operating environment running SQL Server 2005 must have a processor license for each processor that the virtual machine accesses. If a copy of SQL is running on a physical operating environment, then processor licenses are required for all of the processors on that physical server.
SQL and Multi-Core Processors
Multicore processors, which consist of multiple processing execution units or “cores” on one chip, are seen as a promising way to boost computing power. Microsoft has been driving thought leadership in this area by charging the same amount per processor, regardless of how many cores are in the processor. In contrast, Oracle views each “core” as three-quarters of a processor and “rounds up” to the closes whole number for each processor. IBM has a dual policy where customers with x86 platforms are charged per processor and customers on IBM’s POWER5-based systems are charged per core.
Multicore. In each of these scenarios, a single processor license is required for SQL Server
Next time – Multiplexing………………..