IBM E16RMLL-I Implementation Guide - Page 535

THROUGHPUT thresholds, COLLOCATION

Page 535 highlights

Tip: If SELFTUNEbufpoolsize is set to YES, expire inventory processing will also trigger the buffer pool performance monitoring algorithm to check whether a performance improvement could be gained (based on previous server execution and available real memory). THROUGHPUT thresholds Use the THROUGHPUTTIMETHRESHOLD and THROUGHPUTDATATHRESHOLD to control how Tivoli Storage Manager handles slow performing client sessions. Slow performing sessions may pin your recovery log and result in slower overall server performance. These options allow you to specify thresholds that must be met by client sessions in order to be considered productive and avoid cancellation. The THROUGHPUTDATATHRESHOLD is specified in kilobytes per second, and specifies the throughput that a client session must reach to prevent being cancelled after the time threshold is reached. The THROUGHPUTTIMETHRESHOLD is specified in minutes, and is added to the media wait time, to determine the total client session time. It specifies the time threshold for a session after which it may be cancelled for low throughput. If the server detects that the client data transfer rate is below the specified threshold, the session is considered to be eligible for termination after the time threshold is reached. COLLOCATION The speed at which you can restore the files, among other parameters, also depends on how many tape drives are available on the server, and whether you are using collocation to keep file spaces assigned to as few volumes as possible. With tape capacities becoming larger and larger, collocation by groups of nodes is now supported. Groups of nodes can be defined, and the server can then collocate data based on these groups. Collocation by group can yield the following benefits: Reduce unused tape capacity by allowing more collocated data on individual tapes. Minimize mounts of target volumes. Minimize database scanning and reduce tape passes for sequential-to-sequential transfer. For newly defined storage pools, the default storage pool collocation setting is now group. Chapter 15. Performance considerations 505

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Chapter 15. Performance considerations
505
THROUGHPUT thresholds
Use the THROUGHPUTTIMETHRESHOLD and
THROUGHPUTDATATHRESHOLD to control how Tivoli Storage Manager
handles slow performing client sessions. Slow performing sessions may pin your
recovery log and result in slower overall server performance. These options
allow you to specify thresholds that must be met by client sessions in order to be
considered productive and avoid cancellation.
The THROUGHPUTDATATHRESHOLD is specified in kilobytes per second, and
specifies the throughput that a client session must reach to prevent being
cancelled after the time threshold is reached.
The THROUGHPUTTIMETHRESHOLD is specified in minutes, and is added to
the media wait time, to determine the total client session time. It specifies the
time threshold for a session after which it may be cancelled for low throughput.
If the server detects that the client data transfer rate is below the specified
threshold, the session is considered to be eligible for termination after the time
threshold is reached.
COLLOCATION
The speed at which you can restore the files, among other parameters, also
depends on how many tape drives are available on the server, and whether you
are using collocation to keep file spaces assigned to as few volumes as possible.
With tape capacities becoming larger and larger, collocation by groups of nodes
is now supported. Groups of nodes can be defined, and the server can then
collocate data based on these groups. Collocation by group can yield the
following benefits:
±
Reduce unused tape capacity by allowing more collocated data on individual
tapes.
±
Minimize mounts of target volumes.
±
Minimize database scanning and reduce tape passes for
sequential-to-sequential transfer.
For newly defined storage pools, the default storage pool collocation setting is
now
group
.
Tip:
If SELFTUNE
bufpoolsize
is set to YES,
expire inventory
processing will
also trigger the buffer pool performance monitoring algorithm to check
whether a performance improvement could be gained (based on previous
server execution and available real memory).