HP NonStop RDF, Руководство по управлению

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Partitioned Files
All partitions of a partitioned Enscribe file or NonStop SQL table or index must reside on volumes
protected by RDF, or none should. Corresponding partitions on each system must have the same
key values.
CAUTION: For partitioned files, it is essential that the partial key value for Enscribe files or
first key value for NonStop SQL tables on the backup system exactly match those on the primary
system. This is the RDF database administrator’s responsibility.
If you are using RDF to replicate the creation of partitioned files and an RDF takeover operation
occurs in the midst of a set of creations, some partitions might have been created while others
were not, because each partition of a partitioned file is created independently.
Temporary Disk Files
File creation, modification, and updates are not replicated for audited temporary disk files. All
audit data is filtered out by the extractor on the primary system for file names of the form
$
volume
.#
nnnnnnn
.
A filename that begins with # (pound sign) indicates a temporary disk file; this type of file name
is returned when only the volume name is specified in a call to the file-system CREATE procedure
or FILE_CREATE_ procedure.
Using SMF With RDF
RDF supports the full use of SMF on both the primary and backup nodes.
There are two basic ways to configure SMF logical volumes:
• Map many physical disks to a single virtual disk Create SMF pools where each is comprised
of many physical volumes and create SMF virtual disks from these pools. In this configuration,
the files on any given virtual disk will be spread across multiple physical disks allowing
you to pool together many physical disks to create a very large virtual disk.
NOTE: A single updater process can only work on 3000 files at any time. If you have a
virtual disk that has a number of physical disks in its pool, and if the number of files that
need to be updated by the updater assigned to that virtual disk exceeds 3000, the updater
will close some files in order to work on files it does not already have open. If this updater
must regularly work on more than 3000 files, the performance of the updater will be impacted.
For optimal updater performance, you should ensure that no single updater has to work on
more than 3000 files on a regular basis. This might mean that you have to reduce the number
of physical disks in a pool.
• Map many virtual disks to a single physical disk Create SMF pools where each is comprised
of a single physical disk and create SMF virtual disks from these pools. In this configuration,
all the files on a given virtual disk reside on one physical disk allowing you to have a very
large physical disk volume subdivided into a number of smaller logical volumes. In this
way it is possible to have multiple partitions of a file residing on a single physical volume,
with each partition of the file stored on a different logical volume.
Both of these configurations are supported by RDF. There are some restrictions when using SMF
on the backup system which are described in detail later in this chapter.
Using SMF With RDF 65