NEC Storage ReplicationControl SQL Option, Руководство пользователя

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Chapter 4 Functions of NEC Storage ReplicationControl SQL Option
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The metafile created when executing the snapshot backup command is described below.
One metafile is required for each backup.
The metafile contains the target database’s original file configuration and the transaction log state
information.
The file size is approximately several hundred KB. Its maximum size is approximately 1MB.
The metafile can be created on the shared disk, MV or local disk. This metafile is used when recovering
from backup or starting the standby database on another node. Normally the shared disk is used.
When the metafile is lost, snapshot restoration cannot be executed. Therefore, make sure to save it onto
a highly reliable disk.
There respective uses are described below.
•
Shared disk
Used when saving the metafile on the backup server side. The advantage is the ease of saving
metafile.
A disk on the business server or the backup server can be used as a shared disk.
•
MV
Used when the shared disk format cannot be used due to network reasons such as when using an
RV from a remote distance with RDR. Since metafile information is used during recovery, it is
necessary to restore before recovery. At backup, unmount and separate the metafile MV after
snapshot backup.
•
Local disk
Can be used when saving metafile directly from a local volume to a tape or disk. When using the
snapshot backup as a disk backup, it is sufficient to use the local disk for the metafile.
Restore the database file on the RV created with snapshot backup by using the metafile created at the
time.
Attempting to restore the database file by using a metafile created at a different time may cause an
error.
When performing a snapshot backup, note the following:
(1) Metafile (-metafile) specification
•
Overwritten when the specified file already exists.
•
If there is no folder for (or path to) the specified file name, the command fails to create
metafiles which result in an abnormal end.
•
If there is a folder with the same name as the specified file name, the command fails to create
metafiles which result in an abnormal end.
(2) Meta-folder (-metafolder) specification