Intel 7xx Servers User Manual
15.4 Comparing Performance Data
When comparing the performance data in this document with the actual performance on your system,
remember that the performance of save and restore operations is data dependent. If the same backup
device was used on data from three different systems, three different rates may result.
remember that the performance of save and restore operations is data dependent. If the same backup
device was used on data from three different systems, three different rates may result.
The performance of save and restore operations are also dependent on the system configuration, most
directly affected by the number and type of DASD units on which the data is stored and by the type of
storage IOAs being used.
directly affected by the number and type of DASD units on which the data is stored and by the type of
storage IOAs being used.
Generally speaking, the Large Database File data that was used in testing for this document was designed
to compact at an approximate 2.8 to1 ratio. If we were to write a formula to illustrate how performance
ratings are obtained, it would be as follows:
to compact at an approximate 2.8 to1 ratio. If we were to write a formula to illustrate how performance
ratings are obtained, it would be as follows:
((DeviceSpeed * LossFromWorkLoadType) * Compaction) = MB/Sec * 3600 = MB/HR /1000 = GB/HR.
But the reality of this formula is that the “LossFromWorkLoadType” is far more complex than described
here. The different workloads have different overheads, different compaction rates, and the backup
devices use different buffer sizes and different compaction algorithms. The attempt here is to group these
workloads as examples of what might happen with a certain type of backup device and a certain
workload.
here. The different workloads have different overheads, different compaction rates, and the backup
devices use different buffer sizes and different compaction algorithms. The attempt here is to group these
workloads as examples of what might happen with a certain type of backup device and a certain
workload.
Note:
Remember that these formulas and charts are to give you an idea of what you might achieve from
a particular backup device. Your data is as unique as your company and the correct backup device
solution must take into account many different factors.
a particular backup device. Your data is as unique as your company and the correct backup device
solution must take into account many different factors.
The save and restore rates listed in this document were obtained on a dedicated system. A dedicated
system is one where the system is up and fully functioning but no other users or jobs are running except
the save and restore operations. All processors and Memory were dedicated to the system and no partial
processors were used. Other subsystems such as QBATCH are required in order to run concurrent and
parallel operations. All workloads were deleted before restoring them again.
system is one where the system is up and fully functioning but no other users or jobs are running except
the save and restore operations. All processors and Memory were dedicated to the system and no partial
processors were used. Other subsystems such as QBATCH are required in order to run concurrent and
parallel operations. All workloads were deleted before restoring them again.
IBM i 6.1 Performance Capabilities Reference - January/April 2008
©
Copyright IBM Corp. 2008
Chapter 15. Save/Restore Performance
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