Under the simple recovery model , this backup type is available only for a database with a read - only filegroup 在简单恢复模式下，此备份类型只可用于包含只读文件组的数据库。
A backup of all the data in the primary filegroup , every read - write filegroup , and any specified read - only files or filegroups 备份主文件组、每个读写文件组以及指定的只读文件或文件组中的所有数据。
When the keyword all is specified and one or more indexes are in an offline or read - only filegroup , the statement fails 如果指定了关键字all ，但有一个或多个索引位于脱机文件组或只读文件组中，该语句将失败。
This topic is relevant only for databases that contain multiple filegroups and , for the simple - model databases , only for read - only filegroups 此主题仅与包含多个文件组的数据库、简单模式的数据库以及只读文件组相关。
If the database contains multiple filegroups , and you want piecemeal restore of read write secondary filegroups and , optionally , read - only filegroups 数据库包含多个文件组，并且您希望逐段还原读写辅助文件组（以及只读文件组） 。
For instance , it could take a fair amount of testing and rebooting to figure out how to build a system to boot from a read - only filesystem 例如，可能需要进行为数不少的测试和重新引导来搞清楚如何构建一个从只读文件系统进行引导的系统。
After restoring such read - only files from the backup during the data - copy phase of restore , the sql server database engine immediately recovers those files 在还原过程的数据复制阶段，从备份还原这些只读文件之后，数据库引擎将立即恢复这些文件。
However , read - only files that are consistent with the database can be added to the roll forward set without repeating any of the roll forward ; for more information , see 但是，可以将与数据库一致的只读文件添加到前滚集中，无须重复任何前滚；有关详细信息，请参阅
When you restore a read - only file to a filegroup that has read - only since before the backup was created , the file is consistent with the rest of the database , so the redo phase is skipped 还原只读文件组中的只读文件时，如果在还原的备份创建之前文件组就处于只读状态，则跳过重做阶段。
This topic is relevant only for databases in sql server 2005 enterprise edition that contain multiple files or filegroups ; and , under the simple model , only for read - only filegroups 本主题仅与使用完整恢复模式或大容量日志恢复模式，或使用至少有一个只读文件组的简单恢复模式的数据库相关。
