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15.2.1 Database and recovery log
When implementing a Tivoli Storage Manager server, consider using multiple
disk volumes for the database and recovery log files. This enables the server
process to spread its I/O (input/output) over several volumes in parallel, which
increases read and write performance. Subsequently, a greater quantity of
smaller disks can provide better performance than would fewer and larger disks
of the same rotation speed.
To support the above configuration, you may be able to
log volumes across multiple disks, which would balance the I/O load so that it is
not only spread over multiple database volumes, but also over multiple disks.
Note: When spreading your database and log volumes over multiple disks,
ensure that the DB volumes do not share the same physical disks as the LOG
volumes. With this said, when including mirroring for these volumes, again you
should ensure that separate physical disks are chosen for the mirrors as well.
The remaining unused disk space on these volumes can be used to spread
out your disk pools, again ensuring balance I/O.
Another option is to put multiple database volumes on a striped volume set of
disks to increase performance.
When located on separate disk volumes, mirroring can increase not only server
stability, but also server performance. The Tivoli Storage Manager server can
access multiple database copies at the same time and prioritizes the volume
copy with the shortest response time. Thus if your hardware does not support
mirroring, the Tivoli Storage Manager server does this very well, provided that
you balance the I/O with the appropriate volume placement.
Tivoli Storage Manager access to the database for reading/writing is highly
random in nature. Keep in mind that large read-ahead buffers defined for the
volumes might hurt performance rather than help you.
15.2.2 Storage pools
The advice given in the previous section is also valid for disk storage pools, that
is, you can increase performance by using multiple small volumes for disk
storage pools instead of using one big volume.
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IBM Tivoli Storage Manager Implementation Guide
stripe
the database and
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