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Terms and technologies

This section defines the terms and technologies referenced in this guide. Each term or technology is described within a SnapManager-specific context. See the following topics for more information:

backup set  Top

All the data that SnapManager for Microsoft SQL Server requires to perform an individual restore operation.

cluster group  Top

A logical group of cluster resources that can be moved from one node to the other while the nodes remain operational. The cluster group can be moved by the administrator, or it can be moved as a result of a cluster resource failure.

database consistency checker (DBCC)  Top

The Microsoft SQL Server utility for finding and correcting problems in the consistency of the database.

filegroups  Top

A group of files in a user database that have a common logical identity.

host system  Top

A computer that accesses storage on a storage system.

log shipping  Top

A process that takes transaction logs from a primary SQL Server and applies them sequentially on a scheduled basis to another SQL Server. In the event of a failure, an application could be redirected to the other server, which would be only slightly unsynchronized with the primary server or potentially up to date with it, depending on when the last transactions were applied. Log shipping is a means of protecting organizations in the event of a logical or physical system failure.

MSCS  Top

Microsoft Cluster Services. Software that can be added to an SQL Server computer to enable an SQL Server system to operate in standby mode for the primary SQL Server system. SnapManager 2.1 for Microsoft SQL Server supports two-node clusters in a Windows 2000 Advanced Server environment and up to four-node clusters in a Windows Server 2003 Enterprise Edition environment. See also cluster group.

multiple-instance cluster  Top

(Active/Active mode) refers to an MSCS cluster in which two or more SQL Server instances are running on different nodes in the same cluster. Each instance has its own disk resources that cannot be used by other instances. If one system fails, the other system takes over its application services. See also single-instance cluster.

quorum disk  Top

A shared disk resource used by MSCS to keep track of cluster management information, such as cluster resources and state. The quorum disk should not be used for SQL Server files. When SQL Server databases are migrated to LUNs for use with SnapManager, a separate LUN is required for the quorum disk.

recovery model  Top

There are three distinct ways that you can recover your SQL Server environment in the event of a failure. Each model addresses a different need for performance, disk and tape space, and protection against data loss. The three models are summarized as follows:

SIMPLE

You recover the most recent full backup and any differential backups that might exist. Data can be recovered only to the last backup.

FULL

All operations are logged, including bulk operations and bulk loading of data.

BULK_LOGGED

Certain database operations (including SELECT INTO, BULK COPY/BCP, CREATE INDEX, WRITETEXT, and UPDATETEXT) are logged minimally or not at all. Because the BULK_LOGGED recovery model does not provide point-in-time recovery, the risk of data loss is higher than with the FULL recovery model.

For more information, see your Microsoft SQL Server documentation.

single-instance cluster  Top

(Active/Passive mode) refers to an MSCS cluster with SQL Server installed, where only one active instance of SQL Server is owned by a node and all other nodes of the cluster are in a standby state. See also Appendix , multiple-instance cluster.

storage system  Top

Any NetApp storage product that supports FCP (Fibre Channel Protocol) and iSCSI (SCSI over IP).

This guide refers to all NetApp storage products (filers, FAS appliances, and NearStore systems) as storage systems. In other documentation, the terms filer and appliance have also been used to refer to storage systems.

SQL Server 2000 or 2005  Top

A Microsoft relational database system based on the client/server database model.

SQL Server computer  Top

The hardware on which a Microsoft SQL Server 2000 or 2005 database system is running.

system database  Top

A set of five databases created when you install Microsoft SQL Server 2000 or 2005. See also user database. The five system databases are described as follows:

distribution database

A database on the distributor that stores data for replication, including transactions, Snapshot jobs, synchronization status, and replication history information. This is visible, only visible if replication is turned on.

master database

Records the system-level information, SQL Server initialization information, and configuration settings for SQL Server. This database also records all login accounts, the existence of all other databases, and the location of the primary file for all user databases.

tempdb database

Holds temporary tables and temporary stored procedures. This database is also used for other temporary storage needs of SQL Server, such as for sorting data. A clean copy of the tempdb database is re-created at its default size every time SQL Server is started.

model database

Serves as a template for all other databases on the system, including the tempdb database. When a database is created, the first part of it is created as a copy of the contents of the model database. The rest of the database is filled with empty pages. The model database must exist on the system because it is used to re-create tempdb every time SQL Server is started. You can alter the model database to include user-defined data types, tables, and so on. If you alter the model database, every database you create will have the modified attributes.

msdb database

Holds tables that SQL Server Agent uses for scheduling jobs and alerts and for recording operators (those assigned responsibility for jobs and alerts). This database also holds tables used for log shipping and for backup and recovery.

transaction log  Top

A file in the database that is used to record all modifications to the database. Information about the transactions that perform modifications is also kept in the transaction log. The transaction log stores enough information to undo a transaction (in case a rollback is necessary) or to redo a transaction (in case a transaction needs to be rolled forward).

user database  Top

A database created by an SQL Server user and used to store application data. Most users connecting to instances of SQL Server reference user databases only, not system databases. See also system database.

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